Tuesday, March 18, 2014

Tai Chi & Circuit Training Have Both Beneficial Effects on BP of Middle-Aged Women, But Only "True Exercise" Will Cut 6.5% Body Fat While Increasing Lean Mass by 1.8%

It's a beautiful sight (and site) - that's for sure, but compared to "true" exercise doing Thai Chi in the bay is not exactly going to yield live-changing results.
Ok, I have to admit, I am a dopamine junkie, and probably that's because I suck at everything that's slow and takes time... but enough of these personal details. After looking at the study outcomes you will certainly agree: True exercise - in this case in the form of circuit training - will always prevail!

But let's tackle one thing after the other. The study we are looking at was conducted at the Chang Gung Memorial Hospital at Chia Yi and Chang Gung University (wherever that may be.... well, obviously in China). The participants were 180 women (aged 45–75 years) who were divided into a circuit exercise group, Tai Chi group and a control group.

What did the women do?

Well, actually I would first like to point out that there was one thing, the women did not do and that's restricting their food intake. The reason I mention this is that there are dozens, ... no, actually there are hundreds of trials where working out alone had beneficial effects on blood pressure, blood glucose management and / or blood lipids, but did not do what most people are eventually secretly hoping for, whenever they talk about living healthier: It did not induce any changes in body composition.
I like to make fun of it, but the benefits of Tai Chi are beyond doubt. In a 2009 study, scientists from the Universiti Kebangsaan Malaysia confirmed that Tai Chi can (just like "real exercise" ;-) stimulate endogenous antioxidant enzymes and reduce the oxidative damage to proteins, fats and your DNA strands (Goon. 2009).
In the study at hand, in the course of which the subjects participated in 60 min of exercise three times per week for 12 weeks. This was different - at least in those women who actually "exercised", i.e. those who had been randomized to the Circuit Training group and had to endure the following exercise program:
  • The exercise program was 1 h of circuit training, three times per week for 12 weeks, and included aerobic training, resistance training and stretching exercise (20 min per intervention).  
  • Aerobic exercises consisted of any two of the following modalities for 10 min each: treadmill, stationary bicycle, stair climber or elliptical machine exercise. The intensity of the aerobic exercise was set as 60–80% of maximal heart rate. 
  • Two sets of six different resistance exercises were completed through the combined use of hydraulic resistance training machines (side bending machine; biceps curl machine, leg extension machine, seated dip machine, pec dec fly machine, shoulder press machine, hip abductor/adductor machine, chest press machine and leg press machine). The intensity of resistance training was set at 60–80% of one-repetition maximum (RM). To minimize fatigue, the exercises were alternated between the upper and lower body. There was a rest interval between sets of 40 s, but no pauses between repetitions. 
The exercise session were guided and supervised by trained fitness instructors and the researchers - so cheating was not allowed. The latter was probably also the case in the The Tai Chi group that practiced Yang style (watch the next best video I could find) with the same frequency, but with intensity of 50–60% of work.
Figure 1: Changes in total muscle, total lean mass, bone mineral content, body fat and basal metabolic rate in 180 middle-aged women (aged 45–75 years) according to training type (Hsu. 2014)
Based on the introduction you will probably already have expected what you see in Figure 1, the circuit exercise group showed a significant decrease in body mass index, systolic blood pressure and body fat mass, and an increase in total body muscle mass, lean body mass, bone mineral content and basal metabolic rate. The Tai Chi group recorded nothing but a decrease in systolic blood pressure.

In other words, the increase in basal metabolic rate (1.3±3.0%), total body muscle mass (1.8±4.3%), lean body mass (1.9±4.3%) and bone mineral content (1.8±4.2%), and decreases in body mass index (–2.2±7.8%), body fat (–6.5±10.7%) and diastolic pressure (–1.2±9.4%) were significantly greater in the circuit exercicise group... malicious gossip has it that all of these changes were pathetic in the Tai Chi group, but from a science perspective this is obviously not true. From a science perspective, there simply were no changes in basal metabolic rate, total body muscle mass, lean body mass, bone mineral content, body mass index and body fat ;-)
No, I am serious. If you are lucky and mediation is for you - do it! Yet not instead, but in addition to real exercise.
So what's the verdict then? Tai Chi sucks? I guess I have been teasing Tai Chi long enough. I don't doubt it's benefits as a form of meditative exercise and the improvements in diastolic blood pressure Hsu et al. observed in the study at hand confirms that this is more than a psychological benefit.

The real bottom line of the study at hand is thus do real exercise first and make some additional room in your schedule for Tai Chi or other forms of mediation (see my post on the anti-fatigue effect of Qui Gong | read more), if possible. Your mind and body will be greatful... irrespective of whether you're a middle aged woman or a young male athlete, by the way.
  • Goon, J. A., et al. "Effect of Tai Chi exercise on DNA damage, antioxidant enzymes, and oxidative stress in middle-age adults." Journal of physical activity & health 6.1 (2009).
  • Lan, Ching, et al. "The aerobic capacity and ventilatory efficiency during exercise in qigong and tai chi chuan practitioners." The American journal of Chinese medicine 32.01 (2004): 141-150.