Increased physical activity levels can elevate body temperature, metabolic rate and therefore heat production, which can result in raised levels of perspiration (loss of water) and depletion of electrolytes such as sodium, zinc, magnesium and potassium and muscle and liver glycogen stores. The importance of maintaining adequate fluid levels at any time, never mind when training is vital to maintaining homeostasis i.e. normal internal and external bodily function. Vast amounts of research supports the use of isotonic drinks and prolonging exercise, enhancing hydration levels and maintaining electrolyte balance, as well as maximising concentration. In addition to this, brand new research by Mareno, Pastre, Ferreira et al. (2013) published in the Journal of the International Society of Sports Nutrition has reinforced the benefit of isotonic drinks on concentration and neural function, but also on the potential autonomic regulation of cardiac function post exercise too! This could prove to be beneficial to both new and existing sport/exercise enthusiasts and professionals alike.
Here’s what they found:
Do not be deterred, but those people that exercise relatively infrequently are at an elevated risk of suffering irregular heart rhythms known as arrhythmias both during and after exercise, these are obviously not desirable and are not generally dangerous, but it is acknowledged that in some extreme cases arrhythmias have been known to be fatal. Heart Rate Variability (HRV) is the term used to describe the variation of time between heartbeats, and isotonic beverages appear to increase the recovery rate from these HRV’s.
So it appears that isotonic drinks not only aid hydration and energy replenishment during and after training, but the electrolyte levels might also help to maintain blood volume and osmolality (level of solute/electrolyte per litre of solution/blood). This could enable the heart to recover more effectively in turn supporting your recovery, helping you to reach your training goals more effectively!
Moreno, I, L., Pastre, C, M., Ferreira, C., De Abreu, L, C., Valenti, V, E & Vanderlei, L, C. (2013). Effects of an isotonic beverage on autonomic regulation during and after exercise. Journal of The International Society Of Sports Nutrition. 10: 2.