Bright Light Exposure Improves Your Workouts Sign. (~8%)

Would be interesting to compare sunlight and artificial light in future studies.

You will remember the circadian rhythm series in which I have previously discussed the relevance of light exposure as a means to set, reset and entrain your internal clock in order to reap all sorts of health and performance benefits.

Bright (>4000 lux), preferable blue (at least having a blue component) light has repeatedly been shown to increase athletic performance. Studies like Kantermann et al. (2012) show, however, that the efficacy of bright light exposure significantly depends on the chronotype of an athlete.

Learn more about the health effects of correct / messed up circadian rhythms

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In said study, the athletes were exposed to 4420 lux for 120 min before and right before a 40-min time trial. Significant performance increases were observed only for those subjects, though, who were performing ∼14.8 h after their midpoint of sleep on free days (MSFsc). Subjects who trained "earlier" on their internal clock (in this case ∼11.8 h after the MSFsc), on the other hand, did not record any benefits.

Back in the day, Kantermann et al. speculated that a short(er) exposure or mudaltion of light intensity and/or timing could likewise have affected their results. Thus, the hypothesis Knaier et al. used in their 2015 contribution to the "light for performance" research was to that different bright light (BL) exposure regimes prior to and during a time-trial applied during the “sensitive” phase of the circadian rhythm result in a dose dependent increase of time-trial power output - meaning: longer exposure and brighter light = maximal performance benefits.

To test this hypothesis the scientists assigned young (25.1 ± 3.1 years) men to three groups with two different light intensities (A = BL, 4420 lx vs. B = ML, 230 lx) for all three randomly chosen exposure times (2h pre + exercise time, 2HEX | 1h pre + exercise time 1HEX | 1h pre 1H).

Figure 1: Study protocol for 2HEX, 1HEX, and 1H. Time-trial: 40 min in duration; bright light/moderate light (BL/ML): continuous randomized exposure (slightly rearranged version of a figurr from Knaier. 2015).

As Figure 1 illustrates we are thus dealing with a total of three trials and their moderate light counter parts which are not illustrated in Figure 1. Thanks to the use of a cross-over design this means that all subjects were exposed to either bright light (BL, 4420 lux) or moderate light (ML, 230 lx).

Figure 2: Total work (in kJ) during the 40-minute time-trial to exhaustion (Knaier. 2015).

The scientists' analyses of the studies results and the normalization of the results according to the subjects' individual chronotype (estimated based on the Munich Chronotype Questionnaire) yielded the following two primary study outcomes:

• Total work performed during the time-trial in kJ in the 2HEX group was significantly higher in the BL setting (527 kJ) than in ML (512 kJ) (P = 0.002), but not in 1HEX (BL: 485 kJ; ML: 498 kJ) or 1H (BL: 519 kJ; ML: 514 kJ) (P = 0.770; P = 0.485). 
• There was a significant (P = 0.006) positive dose–response relationship between the duration of light exposure and the work performed over the three doses of light exposure. 

Overall, the study does therefore confirm that "[a] long duration light exposure is an effective tool to increase total work in a medium length timetrial" - what's new (compared to the previously referenced Kantermann study is the observation that this advantage holds, even if the results are normalized for the subjects' individual chronotype.

Whether and to which extent the "more light equals more performance" equation will hold with (a) even longer or (b) even more intense light, however, is something that will have to be investigated in future dose-response studies. Studies like O'Brien et al. (2000) which has already proven that shortening the exposure time (in this case to 20 minutes only during exercise) will reduce the effects of bright light exposure on cycling performance to zero.

Bottom line: While one hour of bright or 2h of medium intensity light appears to allow for too little 'light accumulation' to have physiologically relevant affects, long duration of exposure to bright light is, as Knaier et al. point out "an effective tool to increase total work at least for the initial phase of a medium length time-trial" (Knaier. 2015); and what's important, the performance increase of ~8% which was observed not just in the Knaier study, but also in a differently designed trial by Thomson, et al. (2015 | cf. Figure 3), is large enough to be relevant for any competing athlete.

Figure 3: A study by Thompson, et al. (2015) suggests that pre-bed exposition to bright light (30 min) can increase the time-trial performance of athletes on the subsequent morning. Since this will also suppress the melatonin levels of practitioners this is yet a strategy that should not be employed regular (competition only).

The results of Knaier are thus in contrast to a similarly recent study by Nelson et al. (2015) who found that acute short-term dim light exposure can actually lower muscle strength endurance (-18%, albeit with high inter-individual variability). Against that background it should be obvious that, even though, bright light exposure is indeed "likely to increase alertness and reduce sleepiness and help athletes to compensate for disadvantages in competitions at unfavorable times and improve performance" (Knaier. 2015). And don't forget - the scientists from the University of Basel are right: "The ideal duration of expo sure to increase performance and simultaneously interfere as little as possible with athletes’ routine still needs to be found" (Knaier. 2015). In fact, even timing and strategies like the pre-evening light exposure that increased the time trial performance in Thomson et al. (2015 | see Figure 3) must be tested as alternatives | Comment on Facebook!

References:

• Kantermann, Thomas, et al. "The stimulating effect of bright light on physical performance depends on internal time." PloS one 7.7 (2012): e40655.
• Knaier, R., et al. "Dose–response relationship between light exposure and cycling performance." Scandinavian journal of medicine & science in sports (2015).
• Nelson, Arnold G., Joke Kokkonen, and Megan Mickenberg. "Acute short-term dim light exposure can lower muscle strength endurance." Journal of Sport and Health Science 4.3 (2015): 270-274.
• O'Brien, Patrick M., and Patrick J. O'Conner. "Effect of bright light on cycling performance." Medicine & Science in Sports & Exercise (2000).
• Thompson, A., et al. "The effects of evening bright light exposure on subsequent morning exercise performance." International journal of sports medicine 36.02 (2015): 101-106.

Phototherapy Doubles Fat Loss (11 vs. 6%) & Improvements in Insulin Sensitivity (40 vs. 22%) and Helps Conserve Lean Mass in Recent 20 Weeks 'Exercise for Weight Loss Trial'

LLLT has also been shown to improve the appearance of cellulite (Jackson. 2013) | Learn more about what really helps against cellulite in this SV Classic

You know that I am not a fan of isolated "exercise / supplement for weight loss trials", but there's one thing I like about them. When the diet is not controlled for and the subjects still lose weight, it is very likely that the intervention is going to work in the real-world, as well. And if the exercise protocol is both manageable and useful, as it was the case in a recent study from the University of Sao Paulo (Sene-Fiorese. 2015), this makes me even more inclined to actually write about the study, even though it may be - from a mere scientific perspective - not provide "bulletproof" evidence of what's the exact cause of the effects, the exercise or supplement, it's effect on energy intake or both.

Learn more about the nuances of dieting and fat loss here, at the SuppVersity

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But let's return to the study at hand: Manageable and useful, in this case, meant three exercise sessions per week with 30 minutes of aerobic training and 30 minutes of resistance training per session.

"During the intervention period, the voluntaries [sic!] followed a combined exercise training therapy. The protocol was performed three times per week and included 30 minutes of aerobic training and 30 minutes of resistance training per session. The aerobic training consisted of running on a motor-driven treadmill (Movement®) between 70 and 85% of maximal heart frequency, which was determined previously by treadmill submaximal test. The resistance exercise training was composed using exercises for the main muscular groups: bench press, leg press, sit-ups, lat pull-down, hamstring curls, calf raises, Straight-Bar Cable Curl (biceps), triceps pushdown, adductor and abductor chairs [see Table 1]. Training loads were successively adjusted, with volume and intensity being inversely modified and the number of repetitions being decreased to between 6 and 20 repetitions for three sets. The training loads were adjusted in each training session and evaluated according to the increase in participants’ strength. Thus, the training was conducted with maximal repetitions (RM)" (Sene-Fiorese. 2015).

For the study, the scientists recruited a total of 64 adult obese women via classic newspapers and magazines as well as electronic media, TV and radio. The inclusion criteria were (i) primary obesity, body mass index (BMI) between 30 and 40 kg/m², (ii) age between 20 and 40 years old. Exclusion criteria were (i) the use of cortisone, anti-epileptic drugs; (ii) history of renal disease; (iii) alcohol intake; (iv) smoking; and (v) secondary obesity due to endocrine disorders. The inclusion and exclusion criteria were assessed by clinical evaluation by physician (endocrinologist).

Table 1: The scientists a resistance training protocol that had previously been used in Foschini (2010)

While the treatment consisted of physical exercise intervention and the individual application of phototherapy immediately after the end of the exercise training session for all volunteers. The scientists randomly assigned the subjects to an active ET-PHOTO and a "SHAM" control group ET-SHAM.

This is a placebo controlled study! I think it's worth highlighting the fact that both groups believed they'd received the treatment, because all subjects had to go to the phototherapy sessions, but the device was actually turned on only for those in the ET-PHOTO, not for those in the ET-SHAM group.

In the ET-SHAM group the device which emits light at a wavelength that's too long for the human eye to actually see it was turned off. Thus the subjects in the SHAM = control group received a simulated phototherapy application ... and yes, that's basically the same thing as the "placebo group" in your average supplement study..

Figure 1: Photo of the Device, Illustration of the Area of Application; Device Information, Irradiation and Treatment Parameters (Sene-Fiorese. 2015).

"The phototherapy equipment was developed by Laboratory Technology Support-LAT, Center for Research in Optics and Photonics Institute of Physics in São Carlos city at University of São Paulo-USP. The device is a prototype equipment that was submitted for registration as a new patent. The device is composed of four plates made of rubberized material measuring 20 by 20 centimeters (cm) each. Each two plates are connected to an electronic control box. The emitters of Ga-Al-As diode Lasers are distributed in the plate every 2.5 cm, totaling 16 emitters per plate and 64 emitters in total. The prototype is illustrated and irradiation parameters are [mentioned in Figure 1]" (Sene-Fiorese. 2015).

As I already hinted at in the previous paragraph, 805 nm is a pretty high wavelength. It's classified as near-infrared (near as in "near, but not in the visible spectrum"), which is too "long" to be seen by human beings... what it was not too long for, though, was to augment the beneficial effects the 48 workouts the subjects performed over the whole study period had on the women's body composition and metabolic health.

Figure 1: Overview of the changes in body comp and glucose metabolism in both groups (Sene-Fiorese. 2015).

What is (imho) pretty astonishing is yet not the fact that benefits occurred, but rather that these benefits were not just statistically significant, but also practically relevant. I mean you will certailny agree, that it makes a difference if you lose 11% or 6% body fat and improve your insulin sensitivity by 40% vs. 22% - right?

If we also take into account that the the scientists observed similarly profound differences when they analyzed the subjects adiponectin levels, which decreased by 7% in the SHAM group (bad) and increased by a whopping 20% (good!) in the PHOTO group, it's really hard to argue that the benefits wouldn't be worth the hassle, even though one may question the accuracy of the body fat / lean mass data which was measured with a body impedance, instead of a DEXA device. Since the overall results do support significant additive effects, there's simply no reason to assume that the BIA data would be incorrect. In addition, BIA is actually relatively useful if you measure relative changes in body composition. If you want a correct one-time reading of your body fat, though, I wouldn't rely blindly on what a BIA device says.

Bottom line: As the authors point out, their latest study "demonstrated for the first time that phototherapy enhances the physical exercise effects in obese women undergoing weight loss treatment promoting significant changes in inflexibility metabolic profile" (Sene-Fiorese. 2015). While I would probably have replaced the grammatically questionable and nondescript phrase"inflexibility metabolic profile" with something more tangible like "insulin sensitivity" or "glucose control," Sene-Fiorese's conclusion is generally right.

The same LLLT therapy has also been shown to almost double the muscle gains in a study with an 8-week eccentric training program | more

Furthermore their findings may be somewhat surprising, but they are by no means unrealistic in view of the existing evidence that demonstrates that phototherapy (or low-level-laser-therapy | LLLT) is effective as an adjuvant tool in non-invasive body countering. It has been shown to help w/ the reduction of cellulite, fatigue, pain, blood circulation, wound healing, lipid metabolism and recovery after exercise (Neira. 2002; Ferraresi. 2010; Aquino. 2013; Paolillo. 2013; Houreld. 2014), as well as to increase  the mitochondrial activity in irradiated cells by up-regulating genes involved in the mitochondrial complexes (Masha. 2013).

Unfortunately, our understanding of the underlying mechanisms that make LLLT so effective is still in its infancy. It is yet most likely that they are mediated on a cellular level by increases in PGC-alpha (the mitochondria builder) and sirtuins like SIRT-1. These proteins are all important regulators of mitochondrial function; and as you may remember from previous SuppVersity articles, they are also activated by resveratrol and a bunch of other supplements that have been shown to increase the health of the cells' mitochondria. How exactly the previously reported increases in muscle gains or the profoundly accelerated fat loss in the study at hand are brought about, will have to be elucidated in future studies, though | Comment on Facebook!

References:

• Aquino Jr, Antonio E., et al. "Low-level laser therapy (LLLT) combined with swimming training improved the lipid profile in rats fed with high-fat diet." Lasers in medical science 28.5 (2013): 1271-1280.
• Ferraresi, Cleber, et al. "Effects of low level laser therapy (808 nm) on physical strength training in humans." Lasers in medical science 26.3 (2011): 349-358.
• Foschini, Denis, et al. "Treatment of obese adolescents: the influence of periodization models and ACE genotype." Obesity 18.4 (2010): 766-772. 
• Houreld, Nicolette N. "Shedding light on a new treatment for diabetic wound healing: a review on phototherapy." The Scientific World Journal 2014 (2014).
• Masha, Roland T., Nicolette N. Houreld, and Heidi Abrahamse. "Low-intensity laser irradiation at 660 nm stimulates transcription of genes involved in the electron transport chain." Photomedicine and laser surgery 31.2 (2013): 47-53.
• Neira, Rodrigo, et al. "Fat liquefaction: effect of low-level laser energy on adipose tissue." Plastic and reconstructive surgery 110.3 (2002): 912-922.
• Paolillo, Fernanda Rossi, et al. "Infrared LED irradiation applied during high-intensity treadmill training improves maximal exercise tolerance in postmenopausal women: a 6-month longitudinal study." Lasers in medical science 28.2 (2013): 415-422.
• Sene‐Fiorese, Marcela, et al. "The potential of phototherapy to reduce body fat, insulin resistance and “metabolic inflexibility” related to obesity in women undergoing weight loss treatment." Lasers in Surgery and Medicine (2015).

Low Level Laser Therapy (LLLT) Almost Doubles Muscle Gains & Ramps Up Concentric & Eccentric Peak Torque Development During 8-Week Eccentric Training Program

No, this is no photo from the study. Obviously the LLLT was applied to the legs, but LLLT is also used for shoulder and general muscle pain.

I am usually very skeptical when it comes to therapies that sound extremely cool on paper, but have hitherto only proven to improve markers of muscle damage and/or growth. Before I saw the latest paper from the Universidade Federal de Ciências da Saúde de Porto Alegre (Baroni. 2015) low level laser therapy aka LLLT fell into this exact category of promising, but not proven post-exercise recovery therapies (Baroni 2010a, b).

Said study involved thirty healthy male subjects without previous training/LLLT experience were randomized into three groups.

Read more short news at the SuppVersity to learn more about training & nutrition.

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The subjects in the control group remained sedentary for the whole 8-week study period. The subjects who had been randomized to the training (TG) and training + LLLT (TLG) groups, on the other hand, were engaged in an 8-week knee extensor isokinetic eccentric training program.

Figure 1: Application points (black circles) used for LLLT (Baroni. 2014)

"Volunteers allocated in TG and TLG were engaged in an 8-week knee extensor eccentric training program. Training sessions were performed twice a week (except for the 1st and 5th weeks), with a minimum interval of 72 h between ses sions. Subjects performed only one training session in the 1st training week to allow for progressive introduction to the training regimen and to avoid having participants undertake an exercise session in the presence of clinical symptoms of exercise-induced muscle damage, such as delayed onset mus cle soreness (Byrne et al. 2004). At the 5th training week, only one training session was performed because the training volume was increased from three to four sets of 10 maximal eccentric contractions.

Each training session was initiated by a 5-min warm-up exercise on a cycle ergometer, followed by eccentric exercises on the isokinetic dynamometer performed according to the protocol of Baroni et al. (2010a). Before each eccentric contraction, the limb was extended passively to 30° of knee flxion and subjects were encouraged to per form a maximal contraction of the knee extensor as soon as the dynamometer arm reached this position. In response to the subject’s extensor torque, the dynamometer drove the seg ment to 90° of knee flxion (range of motion = 60°) at an angular velocity of 60° s−1. A 1-min rest period was respected between sets and verbal encouragement was provided by team throughout the training session" (Baroni. 2014).

Obviously, only the subjects from TLG were treated with LLLT (wavelength = 810 nm; power output = 200 mW; total dosage = 240 J) before each training session, too.

Figure 2: Muscle size and peak torque changes over the course of the 8-week study (Baroni. 2014).

Knee extensor muscle thickness and peak torque were assessed through ultrasonography and isokinetic dynamometry, respectively; and as the data in Figure 2 indicates. Using the low-level laser therapy using a Thor Photomedicine infra-red laser cluster probe consisting of fie GaAlAs laser diodes (810 nm) immediately before each training session with the probe held stationary in skin contact at a 90°
angle with slight pressure had significant effects on the outcome of the 8-week eccentric strength training protocol.

How exactly does this work? On a molecular level LLLT has been shown to increase the body's natural anti-oxidant activity (Avni. 2005), boost the mitochondrial respiratory chain activity (Silveira. 2009) and increase the ATP production (Karu. 1995). In conjunction, these effects are probably the reason for both the performance and hypertrophy enhancing effects of LLLT. Further studies are yet warran- ted to identify how they add up / interact.

I am still a bit concerned that most of the research comes from one research group only. Nevertheless, the evidence that the previously recorded LLLT induced decreases in muscle damage (Baroni. 2010a) and fatigue (Baroni. 2010b) are practically relevant in terms of increased size and strength gains is finally there. Whether this warrants spending the money on an expensive LLLT device does yet remain just as questionable as the usefulness of cheaper copy cat machines you can buy on the Internet.

That being said, I will keep you in the loop as far as future studies are concerned. Studies of which I hope that they will (a) use previously trained athletes and (b) a more realistic leg workout that incorporates leg presses and/or squats, as well. These studies would complement the evidence we have from acute studies which have already proven the efficacy of phototherapy after both resistance training (Ferraresi. 2011) and endurance training sessions (de Brito. 2012). | Comment on Facebook!

References:

• Avni, Dorit, et al. "Protection of skeletal muscles from ischemic injury: low-level laser therapy increases antioxidant activity." Photomedicine and Laser Therapy 23.3 (2005): 273-277.
• Baroni, Bruno Manfredini, et al. "Low level laser therapy before eccentric exercise reduces muscle damage markers in humans." European journal of applied physiology 110.4 (2010a): 789-796.
• Baroni, Bruno Manfredini, et al. "Effect of light-emitting diodes therapy (LEDT) on knee extensor muscle fatigue." Photomedicine and laser surgery 28.5 (2010b): 653-658.
• Baroni, Bruno Manfredini, et al. "Effect of low-level laser therapy on muscle adaptation to knee extensor eccentric training." European journal of applied physiology (2014): 1-9.
• Byrne C, Twist C, Eston R. Neuromuscular function after exercise-induced muscle damage: theoretical and applied implications. Sports Med 34 (2014):49–69.
• de Brito Vieira, Wouber Hérickson, et al. "Effects of low-level laser therapy (808 nm) on isokinetic muscle performance of young women submitted to endurance training: a randomized controlled clinical trial." Lasers in medical science 27.2 (2012): 497-504.
• Ferraresi, Cleber, et al. "Effects of low level laser therapy (808 nm) on physical strength training in humans." Lasers in medical science 26.3 (2011): 349-358.
• Karu, T., L. Pyatibrat, and G. Kalendo. "Irradiation with He Ne laser increases ATP level in cells cultivated in vitro." Journal of Photochemistry and photobiology B: Biology 27.3 (1995): 219-223.
• Silveira, Paulo CL, et al. "Evaluation of mitochondrial respiratory chain activity in muscle healing by low-level laser therapy." Journal of Photochemistry and Photobiology B: Biology 95.2 (2009): 89-92.

Let There Be Light: 10 New Studies to Enlighten You About the Health Effects of Light Exposure on Health & Physique

No, the sun does not kill you. If you control your exposure it may extend your life and improve your life-quality significantly.

It's about time to "let there be light" to illuminate the benefits of regular well-timed exposure to sunlight and it's short frequency component. Only recently, researchers from the Japanese National Institute of Advanced Industrial Science and Technology (AIST) were able to show that daytime light exposure has significant beneficial effects on cognitive brain activity. Significant enough to have the subjects perform better on an oddball task and to significantly increase cortical activity related to cognitive processes (Okamoto. 2014).

But is that really all, bright light, or more specifically, the regular and well-timed exposure to bright light can do for you?

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Certainly not. I mean if it's ill-timed, like the evening use of light-emitting eReaders it will negatively affect your sleep, mess up your circadian rhythm and decrease your alertness on the next morning. Similar results, i.e. drowsiness and suppression of energy metabolism the following morning, have been reported by other studies, as well (Kayaba. 2014).

As a SuppVersity reader you do yet know all about those negative effects from the circadian rhythm series, anyway. Reason enough for me, to focus primarily on all the good stuff, the well-timed exposure to bright light can do for you in today's Special of the SuppVersity Short News.

• If you can't let go off your mobile at night, use blue blocker glasses as a countermeasure for alerting effects of evening light-emitting diode screen exposure - According to researchers from the Psychiatric Hospital of the University of Basel, blue blocker glasses (BB) significantly attenuate LED-induced melatonin suppression in the evening and decrease vigilant attention and subjective alertness before bedtime.
  
  Strangely, though, visually scored sleep stages and behavioral measures collected the morning after were not modified. Still, van der Lely et al. conclude: "BB glasses may be useful in adolescents as a countermeasure for alerting effects induced by light exposure through LED screens and therefore potentially impede the negative effects modern lighting imposes on circadian physiology in the evening "(van der Lely. 2014).
• UV-light protects against "brainflammation" in MS model - Scientists from the University of Wisconsin-Madison report in their latest paper that UV light selectively inhibits spinal cord inflammation and demyelination in experimental autoimmune encephalomyelitis.
  
  Previous studies have already shown that UV radiation (UVR) can suppress experimental autoimmune encephalomyelitis (EAE), an animal model of multiple-sclerosis (MS), independent of vitamin D production. The mechanism of this suppression did yet remain to be elucidated, until Wang et al. (2014) observed that UVR (10kJ/m²) does not just inhibit the inflammation and demyelination of the spinal cord, but will also dramatically and significantly reduce spinal cord chemokine CCL5 mRNA and protein levels.
  
  In conjunction with an increased production of intereron-gamma (IFN-γ) and IL-10, which are actually used to treat all sorts of autoimmune diseases, artificial and natural UV light can thus actually "prevent the migration of inflammatory cells into the CNS" (Wang. 2014).

• 

  Melatonin conc. after 4 days w/ dim vs. bright light and tryptophan rich vs. poor breakfast (Fukushige. 2014).

  Bright light in the AM and the consumption of a breakfast that's high in tryptophan can help you maintain a healthy circadian rhythm - In case you are asking yourself how you can grasp all the benefits that are associated with having an intact circadian rhythm, you may be intrigued to hear that researchers from the Fukuoka Women's University have been able to show that an increase in tryptophan intake at breakfast combined with daytime light exposure has beneficial effects on melatonin secretion and sleep quality. As you can see in the figure to the left it will significantly elevate the evening melatonin peak, which is critical for an optimal circadian rhythm.
  
  If you are looking to optimize your internal clock bright light (either sunlight or a 10,000 Lux daylight lamp) + tryptophan (seeds, nuts, soy, cheese, chicken, turkey, fish, oats, beans and eggs are the TOP10 sources) are the way to go. If you want an extra "kick" add some coffee to the equation. This will increase the light responsiveness of the circadian pacemaker - well, at least in mice it does (Diepen. 2014).

If you want to design your own "dawn simulator" that's the spectrum you need (Virginie. 2014).

Wanna be smarter, but can't get enough sleep? Start your day with a dawn simulation: Chronic sleep restriction (SR) has deleterious effects on cognitive performance that can be counteracted by light exposure. Scientists from the Psychiatric Hospital of the University of Basel have recently been able tho show that a dawn simulating in the AM will increase your task performance throughout the day after morning; and what's best: The benefit was most pronounced in those participants who sucked the most when they didn't get a good night's sleep (Virginie. 2014).

• Bright lights at work will keep you sane, happy and alert - If you are working in an insufficiently lit office without natural sunlight, you should be prepared to develop physiological, sleep and depressive symptoms.
  
  Assuming you have a window in your office, you will get a significantly more pronounced total and peak exposure to bright light that's going to correlate with 33% reduced levels of the stress hormone cortisol, a more natural rhythm of melatonin and a reduced risk of minor psychiatric disorders and depressive symptoms (MA) in the evening.
  
  That's at least what the results of a recent study from the UFRGS in Porto Alegre indicates (Harb. 2014). A study the authors of which proudly say that their "study demonstrated that not only may light pollution affect human physiology but also lack of exposure to natural light is related to high levels of cortisol and lower levels of melatonin at night, and these, in turn, are related to depressive symptoms and poor quality of sleep" (Harb. 2014).

• 

  If you want to light up the darkness, when it's actually time to sleep do it with green (555nm) or red, not blue light, which suppresses melatonin (Bonmati-Carrion. 2014).

  Staying away from nightly night exposure may also help to keep your arteries clean even in the old age - Studies indicate that even after  adjustment for confounding factors, including age, gender, body mass index, current smoking status, hypertension, diabetes, dyslipidemia, sleep medication, estimated glomerular filtration rate, nocturia, bedtime, duration in bed (scotoperiod), day length (photoperiod), urinary 6-sulfatoxymelatonin excretion and daytime and nighttime physical activity, exposure to light at night is associated with carotid intima-media thickness (Obayashi. 2014).
  
  If you don't want to develop subclinical carotid atherosclerosis, when you are old, it would thus be a good idea to adhere to the basic rules of sleep hygiene: a dark room and/or blindfolds will keep your arteries clean and may thus save your life ;-)
• If you have kidney problems, get out in the sun if you want to survive - Scientists from the University of California Irvine Medical Center were able to show that dialysis patients residing in higher UV index regions have lower all-cause mortality compared to those living in moderate-high UV regions (Shapiro. 2014).
  
  More specifically, the ~60year-old subjects residing in moderate-high UV index regions had a 16% reduced risk of all-cause mortality. Those living in very-high UV index regions had a 1% higher risk reduction (17%). Interestingly, there was a similar inverse association between UV index and mortality was observed across all subgroups, but it was more pronounced among whites vs. non-whites.
• Wear those shades (or bluelight blocker glasses) before any important sport event - Why? Stupid question. If you dabble around with your smartphone "unprotected" the evening before an important sport event for only 30 minutes, this can influence exercise performance under hot conditions during the subsequent early morning (Thompson. 2014).

Even brief light exposure, when your eyes are closed messes with your circadian rhythm.

Pah, when your eyes are closed, light is not a problem, right? Wrong. Even ,illisecond flashes of light phase delay the human circadian clock during sleep. While a greater number of matched subjects and more research will be necessary to ascertain whether these light flashes affect sleep, data from a recent study from the California Mental Illness Research Education and Clinical Center suggest that 2-msec light flashes given every 30 sec have an effect on the circadian rhythm of healthy volunteers. And while Zeitzer et al. (2014) tried to use the flashes to modify the rhythm in a beneficial way, the exact opposite can also be the case. It all depends on how / when you are exposed to light when you sleep.

Sleep disturbance and adaptive immunity. Following a night of sleep loss, or during a period of sleep disturbance, nerve fibers from the sympathetic nervous system (SNS) release the neurotransmitter norepinephrine into primary and secondary lymphoid organs and stimulate the adrenal gland to release stored epinephrine into systemic circulation. Both neuromediators stimulate leukocyte adrenergic receptors (e.g., ADRB2) and activate nuclear factor (NF)-κB-mediated inflammatory programs (Irwin. 2015).

• If your grandparent's have Alzheimer's install a timer-based light system - This may not just increase their sleep quality, but it will also improve their behavior and mood as indicated by reduced depression scores on the Cornell Scale for Depression in Dementia and agitation scores from the Cohen-Mansfield Agitation Inventory (Figueiro. 2014).
  
  I must warn you, though: The recent field study from the Rensselaer Polytechnic Institute is promising, but the results should be replicated using a larger sample size and perhaps using longer treatment duration.
• If you have to work night shifts consider using 1-5mg melatonin 1h before you go to bed - Why? You have to counter the natural decline in melatonin production that occurs over consecutive days of night work (Dumont. 2014).
  
  In a recent study from the Sacre-Coeur Hospital of Montreal the melatonin production of the healthy volunteers decreased progressively decreased over consecutive days of simulated night work, both during nighttime and over the 24 h. Interestingly, this decrease was larger in women using oral contraceptives and independent of bright light exposure.
• Get out into the sun and cure your back pain - If your back hurts and neither you or your doctor have a clue why, try getting into the sun. A study from the UMIT in Austria shows that only three sessions in front of 5.000 lx lamp improved the depressive symptoms and reduced the pain intensity in CNBP adults with chronic nonspecific back pain (Leichtfried. 2014).

One of the side effects of blue light LED exposure (open circles) in the PM is a sign., but practically prob. irrelevant reduction in energy exp. on the next morning (Kayaba. 2014).

Bottom line: I really hope that I do not have to sum up the results for you. I mean, it should be obvious that sleep hygiene at night and light exposure at day are among the most important factors of the lifestyle-factors in the exercise + nutriton + lifestyle solution to perfect health & obesity protection (Partonen. 2014).

Against that background I would like to use the last lines to put another emphasis on the results of the recent study by Kayaba et al. (2014) which found that one of the negative consequences smartphone junkies have to suffer on the morning after using their devices before bed is a reduction in energy expenditure.

If you take a look at the data in the figure at the right (open circles = exposed; full circles = non-exposed), you will yet realize that this probably isn't the worst side effect of blue-LED light exposure in the evening. The reduction is significant in the AM, yes, but on its own it's not practically relevant | Comment on Facebook!

References:

• Bonmati-Carrion, Maria Angeles, et al. "Protecting the Melatonin Rhythm through Circadian Healthy Light Exposure." International Journal of Molecular Sciences 15.12 (2014): 23448-23500.
• Diepen, Hester C., et al. "Caffeine increases light responsiveness of the mouse circadian pacemaker." European Journal of Neuroscience 40.10 (2014): 3504-3511.
• Dumont, Marie, and Jean Paquet. "Progressive decrease of melatonin production over consecutive days of simulated night work." Chronobiology international 0 (2014): 1-8.
• Figueiro, Mariana G., et al. "Tailored lighting intervention improves measures of sleep, depression, and agitation in persons with Alzheimer’s disease and related dementia living in long-term care facilities." Clinical interventions in aging 9 (2014): 1527.
• Fukushige, Haruna, et al. "Effects of tryptophan-rich breakfast and light exposure during the daytime on melatonin secretion at night." breast cancer 4 (2014): 9.
• Harb, Francine, Maria Paz Hidalgo, and Betina Martau. "Lack of exposure to natural light in the workspace is associated with physiological, sleep and depressive symptoms." Chronobiology international 0 (2014): 1-8. 
• Irwin Michael, R. "Why Sleep Is Important for Health: A Psychoneuroimmunology Perspective." Annual Review of Psychology 66 (2015): 143-172.
• Kayaba, Momoko, et al. "The effect of nocturnal blue light exposure from light-emitting diodes on wakefulness and energy metabolism the following morning." Environmental health and preventive medicine 19.5 (2014): 354-361. 
• Leichtfried, Veronika, et al. "Short‐Term Effects of Bright Light Therapy in Adults with Chronic Nonspecific Back Pain: A Randomized Controlled Trial." Pain Medicine 15.12 (2014): 2003-2012.
• Obayashi, Kenji, Keigo Saeki, and Norio Kurumatani. "Light exposure at night is associated with subclinical carotid atherosclerosis in the general elderly population: The HEIJO-KYO cohort." Chronobiology international 0 (2014): 1-8.
• Okamoto, Yosuke, and Seiji Nakagawa. "Effects of daytime light exposure on cognitive brain activity as measured by the ERP P300." Physiology & behavior 138 (2015): 313-318.
• Partonen, Timo. "Obesity= physical activity+ dietary intake+ sleep stages+ light exposure." Annals of medicine 46.5 (2014): 245-246.
• Shapiro, Bryan B., et al. "The Relationship Between Ultraviolet Light Exposure and Mortality in Dialysis Patients." American journal of nephrology 40.3 (2014): 224-232. 
• Thompson, A., et al. "The Effects of Evening Bright Light Exposure on Subsequent Morning Exercise Performance." International journal of sports medicine EFirst (2014).
• van der Lely, Stéphanie, et al. "Blue blocker glasses as a countermeasure for alerting effects of evening light-emitting diode screen exposure in male teenagers." Journal of Adolescent Health (2014).
• Virginie, Gabel, et al. "Dawn simulation light impacts on different cognitive domains under sleep restriction." Behavioural Brain Research (2014).
• Wang, et al. "UV light selectively inhibits spinal cord inflammation and demyelination in experimental autoimmune encephalomyelitis." Arch Biochem Biophys. (2014). [Epub ahead of print]
• Zeitzer, Jamie M., et al. "Millisecond Flashes of Light Phase Delay the Human Circadian Clock during Sleep." Journal of biological rhythms (2014): 0748730414546532.

Wake-Up Light as Natural Ergogenic: Dawn Simulation Increases Early Morning Physical & Cognitive Performance

What could be better than starting your day with the first rays of the sun? Doing this with a person you love, I suppose.

If you have listened to Super Human Radio earlier this week (download episode), you will have heard that Carl "caught" me off guard calling me without prior notice during the live show. We ended up talking about the use of melatonin and my beloved "daylight lamp" (light therapy lamp), which kept my energy levels up even at the darkest winter mornings over the past couple of months.

If you listened to the show, you may also remember that Carl mentioned that it would be great to have a light-based alarm clock - something like a light therapy lamp that increases its intensity gradually at a given time and will thus wake you up from a deep slumber.

You can learn more about sleep and the circadian rhythm at the SuppVersity

Sunlight, Bluelight, Backlight and Your Clock

Sunlight a La Carte: "Hack" Your Rhythm

Breaking the Fast to Synchronize the Clock

Fasting (Re-)Sets the Peripheral Clock

Vitamin A & Caffeine Set the Clock

Pre-Workout Supps Could Ruin Your Sleep

Well, I already mentioned during the show that a corresponding device is already available, but pretty useless for someone who usually uses blindfolds to get a good night's sleep. For the rest of you, who are sleeping in a pitch black room without covering their eyes with a blindfold, on the other hand, Carl's suggestion could be a viable means to "improve both cognitive and physical performance after waking." (Thompson. 2014).

This is at least what a recent study from the University College London would suggest. For the corresponding experiment, the researchers from the Department of Epidemiology and Public Health recruited 8 young adults (four males; four females) with a mean age of 24 ± 9 years who had not been involved in nocturnal shift work or undertaken transmeridian travel during the past 30 days (that's important to ensure that their circadian rhythm was not messed up in the first place).

Dawn Simulation? How did that work? Two dawn simulation devices (Lumie Bodyclock Active 250) were placed at either side of the participants’ bed at a distance of 30 cm to ensure they were exposed to the light. thirty minutes prior to waking, dawn simulation was initiated, starting at 0.001 lux and rising to 300 lux following a sigmoidal illumination ramp. Accuracy was confirmed by measurement of illuminance with a digital photometer.

The trials themselves were ordered in a counterbalanced fashion and were separated by 5–9 days. In the two days leading up to the tests, the participants were asked to sleep the exact times in their own homes that they would in the laboratory. to monitor compliance wrist accelerometers were issued.

Did you know that previous studies support the use of dawn simulations to tread seasonal effective disorder, where it was on top of that associated with lower remission rates than regular light therapy (Avery. 1993 & 2001). In addition, dawn simulations have been shown to have beneficial effects on the necessary and natural and healthy (Clow. 2010) early morning increase in cortisol (Thorn. 2004)?

"The experimental trials were identical with the exception of the 30 min prior to waking. During this time par ticipants either slept normally in complete darkness, the control condition (c), or were exposed to dawn simulation (DS).

Each night’s sleep ended with an audible alarm. At the same moment, a researcher entered the room to ensure that the participant was awake. Participants were then allowed to attend the bathroom if required.

After waking, a 75 min testing protocol commenced which consisted of: three bouts of cognitive assessment, one physical performance test and monitoring of physiological and subjective variables." (Thompson. 2014)

In view of the fact that I already gave away the results, it's probably not really surprising that the data in Figure 1 confirms that being waken up by artificial sunlight had significant beneficial effects on the cognitive and physical performance of the subjects.

Figure 1: Changes in number of total additions and reaction time in cognitive tests (Thompson. 2014)

What did not differ, though, were the sleep efficiency, sleep latency, and the total sleep time. In a similar vein, the differences in perceived sleepiness and body temperature were visible, but not statistically significant.

The Philips Wake Up Light, I mentioned on the air has a similar 300lux daylight lamp as the device used in the study at hand.

Bottom line: Overall my good friend Carl Lenore was thus (once again) right. Emulating the Sun's "natural" wake-up call will get your body and mind going in the morning. The fact that this worked with only 300 lux and eventually being woken up by the usual nasty alarm clock is telling me that it may be worth checking what happens if you ditch the alarm clock altogether and increase the light intensity from 0 to 10,000 lux so that the light and not the alarm clock wakes you up.

Whether this or the addition of a "post-wake-up" session in front of a light therapy lamp, as the one I use, provides additional benefits, would yet have to be verified in a controlled trial.

References:

• Avery, David H., et al. "Dawn simulation treatment of winter depression: a controlled study." American Journal of Psychiatry 150 (1993): 113-113.
• Avery, David H., et al. "Dawn simulation and bright light in the treatment of SAD: a controlled study." Biological psychiatry 50.3 (2001): 205-216.
• Clow, Angela, et al. "The cortisol awakening response: more than a measure of HPA axis function." Neuroscience & Biobehavioral Reviews 35.1 (2010): 97-103.
• Thompson, Andrew, et al. "Effects of dawn simulation on markers of sleep inertia and post-waking performance in humans." European journal of applied physiology (2014): 1-8.
• Thorn, Lisa, et al. "The effect of dawn simulation on the cortisol response to awakening in healthy participants." Psychoneuroendocrinology 29.7 (2004): 925-930.