Heat Stress and Growth Hormone
Most of the information on this page is taken from Dr Rhona Patrick’s website – http://www.foundmyfitness.com
Here’s her video about responses to heat stress:
To summarise –
Heat stress (e.g. from using a sauna) and adaptation can help increase muscle mass (in theory) by
1. Producing heat shock proteins – (repair oxidative damage, help create net increase in protein synthesis)
2. Increasing HGH synthesis
3. Improving insulin sensitivity
2 x 20 min sauna sessions per day, created a 2 fold increase in HGH levels
2 x 1 hour per day sauna sessions for 7 days, resulted in a 16 fold increase in HGH levels
Heat adaptation also has a positive effect on the brain.
This is not included in the video, but having done a bit of reading up, it appears exercising in the heat (or with loads of layers of clothes on) can cause a change in hormonal responses.
Have a look at this study for example:
The vast body of evidence concerning exercise, core temperature and HGH release suggests that a rise in core temperature above 0.6 degrees Celsius, results in significant increases in HGH levels after training.
In addition, another positive effect of increased muscle temperature, is demonstrated in this study, which demonstrates that elevated temperature, results in increased power and strength output. It’s also generally well known and accepted that increased core and body temperature, leads to decreased likelihood of injuries.
There is also evidence that heat-stress up-regulates endorphin receptors, making you feel extra happy after you finish training 🙂
So exercising in the heat might be worth trying. Remember to keep hydrated though, sipping a 5-10% glucose drink with electrolytes.
M.W. Radomski, M. Cross, A. Buguet, Exercise-induced hyperthermia
and hormonal responses to exercise, Can. J. Physiol.
Pharmacol. 76 (1998) 547–552.
M.C. Cross, M.W. Radomski, W.P. VanHelder, S.G. Rhind, R.J.
Shephard, Endurance exercise with and without thermal clamp:
effects on leukocytes and leukocyte subsets, J. Appl. Physiol. 81
Influence of muscle temperature on maximal muscle strength and power output in human skeletal muscles
Written by Drew Griffiths