Isotonics encourage heart rate recovery

New research shows that consuming isotonic drinks during exercise does not significantly influence heart rate variability (HRV) during exercise - but it does promote faster recovery afterwards.

The results of a study of 31 young males, which analysed the impact of isotonic beverages on HRV has been published in the Journal of the International Society of Sports Nutrition.

It compared the HRV of participants during and after 90 minutes of treadmill exercise.

Significant changes

It found that hydrating with isotonic solution during recovery induced significant changes in cardiac autonomic modulation, promoting faster recovery of linear HRV indices.

Isadora Lessa Moreno, the report's author, said hydration with isotonic solution did not significantly influence HRV during exercise. However, after exercise it promoted faster recovery of linear indices, she added.

"We concluded that regardless of hydration status, the exercise protocol caused alterations in cardiac autonomic modulation, characterised by increased sympathetic and decreased parasympathetic activity," said Lessa Moreno.

Gatorade

Although the isotonic solution administered (Gatorade, Brazil), containing carbohydrates (30g), sodium (225mg), chloride (210 mg) and potassium (60mg) per 500ml of the drink, generally produced lower alterations in HRV indices during exercise, it was not enough to significantly influence the changes in cardiac autonomic modulation.

"Throughout the recovery period, however, the hydration exercise protocol induced significant changes in cardiac autonomic modulation, promoting faster recovery of HRV indices," she added.