Friday, May 3, 2013

Breaking the Fast, Cardio & Your Brain: Cardio on Empty is Fatiguing. Fasting Without Exercise, However, is Nootropic

Boking: Every endurance athletes knows and fears it, so wouldn't just that happen when you do your cardio on empty in the morning? And what about the effects on your brain power? Will your gray matter bonk, as well? And if so, what can be done about it?
Today's SuppVersity post is a little different from the usual "Training on empty? Yes / No / Maybe!" debate that flares up every now and then on almost every fitness related bulletin board of the World Wide Web. And in as much as I would like to say that this was all the credits belong to me, the fact that the the following dissertation may actually make a practically relevant contribution is due to the experimental design of the latest study from the Northumbria University in Newcastle, Tyne and Wear, in the UK (Veasey. 2013).

Why is that? Well, contrary to the majority of breakfast "yes or no" studies this one has both an exercise and and a cognitive performance aspect. Since I suppose that most of you are not living to train, but training to live, this is practically highly relevant. I mean, what's the use of "looking good naked" due to the purported benefits of working out "on empty" first thing in the morning if that reduces your cognitive performance in a way that you risk being fired?

Now that I've got everyone's attention, let's look at what exactly R.C Veasey and her colleagues did to find out whether having / not having breakfast before morning cardio or rest will impact cognitive performance and mood later in the morning. To this ends, the researchers recruited 12 healthy, active men in their early 20s with an average BMI of 24.5 ± 2.0 kg/m², who had to abstain from rigorous exercise and alcohol consumption prior to the exercise trials before they reported back to the lab after a 12h fast.
Do the online stroop test to get an idea of what the subjects in the study had to do and why it may in fact not be ideal to have breakfast when you are not exercising. After all, the results of the study at hand clearly suggest that the the accuracy in the stroop performance test decreases significantly in the "no exercise, but breakfast" condition.
"After confirming compliance to the study restrictions, a baseline completion of the cognitive tasks and mood scales was then undertaken, before participants were administered the test breakfast or remained fasted. During the 2 h rest period which followed, cognitive performance and mood were measured at 60 and 120 min. In between these periods, participants were allowed to read, write or watch a DVD. In the exercise trials (NB E and B E), participants then completed a treadmill run at 60% of their VO2, until 2.9MJ had been expended with heart rate and rate of perceived exertion (RPE) measured at 10 min intervals throughout. [...] On rest days (NB NE and B NE), participants rested for the equivalent amount of time. Cognitive performance and mood were reassessed before participants were administered a test drink, followed by a 90 min rest period where cognitive performance and mood was assessed at 30 and 75 min. This was followed by an ad libitum lunch where participants were asked to consume enough food to feel satisfied to a normal level. After lunch, they completed the cognitive tasks and mood scales for a final time and were then free to leave the laboratory." (Veasey. 2013)
"Hah?" Yeah, that was my initial reaction to the overcomplicated study protocol, but don't worry, after you've taken a peak at the following overview I guess, you will be able to identify how this corresponds to getting up, driving to the gym, working out and head to your working place with or without breakfast.
Illustration 1: Outline of the allegedly somewhat difficult to understand study protocol (Veasey. 2013)
You see? It's not so complicated as the scientists description of the protocol made it appear. Four conditions, total, two conditions with and two without 72g syrup flavor porridge oats with 360ml milk, each repeated twice with or without exercise after the initial rest period - that's all.

"Ok, whatever... what were the results? "

As the scientists had expected, the consuming breakfast prior to exercise did in fact elicit the most beneficial cognitive performance and mood effects following in the exercise conditions.
Figure 1: Cognitive performance, mental fatigue and tension in the four trials (Veasey. 2013)
The data in figure 1 does yet also reveal that having breakfast before rest had detrimental effects on the ability of the study participants' ability to rapidly process visual information and omitting breakfast improved their performance on Four Choice Reaction Time test.

Whey and carbs as cognition booster and stress buffer for breakfast: In view of the results of a soon-to-be-published paper from the University of Helsinki clearly shows that a combination of whey and carbs for breakfast improves coping with mental tasks in healthy subjects compared to the "breakfast" used in the study at hand (Sihvola . 2013), it would appear prudent to remember that, when you rise and shine and decide to have breakfast - regardless of whether you intend to work out, or not (the increased protein intake may even help with the performance decline in the "breakfast, no exercise" condition - emphasis on may and assuming you don't ingest it in isolation just to end up hypoglycemic). Apropops, don't forget: Low GI carbs are your brain's friends (e.g. Micha. 2010; Cooper. 2012)
Bottom line: According to the results of the study at hand, you do have two options to maintain / optimize your "desk performance" (cognitive performance at the job) in the morning hours:
  • either you fast and refrain from working out or
  • you have breakfast and work out
It goes without saying that even minor changes in the protocol, e.g. the omission of the 120min rest period (I gather you don't need that long in the bathroom before you either leave the house and go for a jog, sit on your cycle ergometer or drive to the gym), for example could skew the results in a favorable way for the "non-breakfast condition", if  you don't stick to a meager 250ml of chocolate milk after your workout but indulge a real breakfast (see box on the right for a scientifically warranted suggestion)...

The latter is by the way a practice that has always worked pretty well for me. I did however have to realize that this does only work if you really eat and don't just down a protein, let alone whey shake that will only spike your insulin and send you down into the abyss of borderline hypoglycemia. A state which is certainly nothing your cognitive performance can benefit from (Lindgren. 1996).

Highly suggested read: "Circadian Rhythmicity - "Breakfast" or "Breaking the Fast"? Fasting as Zeitgeber & All About King, Prince & Pauper" (read more)

  • Cooper SB, Bandelow S, Nute ML, Morris JG, Nevill ME. Breakfast glycaemic index and cognitive function in adolescent school children. Br J Nutr. 2012 Jun;107(12):1823-32. 
  • Lindgren M, Eckert B, Stenberg G, Agardh CD. Restitution of neurophysiological functions, performance, and subjective symptoms after moderate insulin-induced hypoglycaemia in non-diabetic men. Diabet Med. 1996 Mar;13(3):218-25. 
  • Micha R, Rogers PJ, Nelson M. The glycaemic potency of breakfast and cognitive function in school children. Eur J Clin Nutr. 2010 Sep;64(9):948-57.
  • Sihvola N, Korpela R, Henelius A, Holm A, Huotilainen M, Müller K, Poussa T, Pettersson K, Turpeinen A, Peuhkuri K. Breakfast high in whey protein or carbohydrates improves coping with workload in healthy subjects. Br J Nutr. 2013 Apr 16:1-10.
  • Veasey RC, Gonzalez JT, Kennedy DO, Haskell CF, Stevenson EJ. Breakfast consumption and exercise interact to affect cognitive performance and mood later in the day: a randomized controlled trial. Appetite. 2013 Apr 19.


RenaissanceMan said...

Hey Prof can you clarify what you do with your personal procedure? I didn't realy understand that last paragraph/sentence


Anonymous said...


My question sort of piggybacks on RM's question. If a person works a normal desk job all day and then trains in the evening, it sounds like their best option to maximize brain performance during the day is either to (1) eating nothing for breakfast or (2) eat a pretty good- sized breakfast with both protein and low-GI carbs (e.g., a whey protein shake and some oatmeal). Is that right?


Primalkid said...

Fasting increases cognitive performance via several mechanisms, not the least of which is simply a rise in the catecholamines and cortisol (which makes you more alert and provides brain fuel via mobilization of fatty acids). However, exercise is very catabolic and takes these effects to the next level (similar to modern america "if some is good, more must be better"; this is not always the case).

Therefore, either skip breakfast and go to work. Or workout and eat your whey and oatmeal.

Neil Gaus said...

I can't help but question the overall conclusion that fasting is better than having breakfast if you're not going to train given the terrible composition of the breakfast meal.

Oats with milk for breakfast would certainly make me tired not too long after the meal, but something like meat and berries or even just eggs would not. I certainly won't be giving up breakfast based on these data.

Adel aka Dr. Andro said...

First, I never strength train in the morning on empty. That does not work for me - same for HIIT. What I have done in the past and certainly will do in the future is doing 40min of light exercise on a bike or (in the summer) go for a 30min of jog "on empty" (usually with a black coffee before and some "sodium bicarbonated" water /roughly 2 teaspoons on 0.5l water to drink while I work out)

Afterwards I shower and eat a normal breakfast with an additional protein shake. That's it. Nothing out of the ordinary I would say.

Adel aka Dr. Andro said...

While your answer is spot on, Alex, it is actually what is already in the article, which is why I gather anonymous (please just type in any name, guys) is probably rather asking about the rest of the day? I would not recommend fasting for the complete day - the "benefits" of increased attention (which is by the way a direct result of higher catecholamine and cortisol levels from skipping breakfast) can easily turn against you and your brain performance. So, the best whey *rofl* would be to have a late breakfast as lunch, I suppose < this would warrant a follow up study, but the low GI high protein meal for lunch is (imho) a must to keep functioning till 4pm, when you leave the office. Plus, if you have a decent lunch to break the fast at 12-1pm you have 4h+ till you train later in the day which gives you all the options of training "on quasi empty" or refill with a snack in-between and you got almost automatically a fasting window of 16h (assuming that you don't ingest any foods past 8pm), which can come handy when you are trying to lose weight (16h is however the max, I believe you can benefit from if you're intermittendly fasting chronically)

Adel aka Dr. Andro said...

one thing is for sure, the increased attention will be gone (see remarks on cortisol and catecholamines in previous answer). Your improved breakfast will yet reduce the negative side effects being psyched up has and it will avoid that you overdo it and bunk later in the day.

Anonymous said...

I’ve noticed that all whey proteins,even lactose-free ones, give me terrible flatulence. I tried egg white protein powder and it caused gas as well. Are there protein powders that do not cause flatulence ? Or any tricks to avoid the mentioned consequence from protein powders ? It is quite annoying to sit in the office all day with a bloated belly ready to explode.

Neil Gaus said...

I have played around with, what I would call, "light" intermittent fasting, fasting approximately 12-13 hours. What I have come to like is putting off breakfast for just a little in the morning, for example waking at 6:30 am and eating around 7:30-8 am, and having a final meal end at 7 pm and go to bed by 10 pm.

What I noticed with pushing back breakfast later is that, now bear with me, I felt more "wired" and I could somehow feel that it was harder on my adrenals (this is coming from a 28 year old that abused ephedra and caffeine for too long). Also in my research, I felt that pushing breakfast back too far into the day would disrupt normal circadian rhythms. Waking up and having a good breakfast within a reasonable time seems to be a potent Zietgeber for peripheral clocks (especially with caloric restriction), and to me, seems like it also helps support the natural rise in body temperature compared to fasting.

What I also noticed is that when I do not eat within 3 hours of bed time, I have a higher quality of sleep (measured by MyZeo sleep monitor). Having a meal closer to bed measurably decreases the quality of sleep, and in my case, particularly decreases deep sleep time. I think it also gives internal organs a rest at the appropriate time, and even things like circadian rhythm of urinary output seems to be normal (meaning not getting up at night to urinate).

And taking a step back away from the data, to me, this type of fasting makes sense. You wake up and have a breakfast a bit later (not immediately), eat during the normal wake phase when you're active, and then discontinue food as you enter the night period, and no food late at night and obviously not throughout the night. You are not restricting a lot in the morning, which I felt had negative effects on my adrenals, body temperature circadian rhythms, plus I just didn't like the feel of it. You also do not fast too long in the evening, which if is extended to long, will totally screw up sleep (worse than a full meal right before bed). There's moderate restriction on both ends without either being very long, and still allows for a 12-13 hour fast very easily, and from my experience, very naturally. It also seems to just make sense that you do eat some time in the morning, eat throughout your normal wake phase, and then don't eat as you enter the night/rest phase. I think the food during the wake phase, along with correct light cues, is the correct Zietgeber to keep central and peripheral clocks working properly.

I think the composition of the meals is important as I mentioned in my previous post, as having a high carb breakfast without much in the way of fat or protein is certainly not setting up your blood sugar or neurotransmitters to support energy and alertness, just as you wouldn't eat a stimulating high protein meal late in the evening.

Neil Gaus said...

Can you skip the protein powders and eat real food instead?

Adel aka Dr. Andro said...

what comes to mind is pea protein. Maybe that works.

That bing said, Neil is right, you can skip the powders, although I suppose you will have similar issues with milk products, as well and that reduces the adequate alternatives

Adel aka Dr. Andro said...

very good point on the Zeitgeber AND most importantly on doing what works for you and putting faith in your own judgement

Furor Germanicus said...

Three simple words: adaption to fast. It takes quite some time to get fond with that idea (and to kick start your day with coffee instead of an rich breakfast). But once you're adapted, its a "jogg in the park" - literally.

If those participants in the NB group were used to eat breakfast regularly (which I imply) then of course they would be anxious...