Hydration and physical activity: staying in top form
Water is an essential exercise partner to counteract the negative effects of dehydration on performance and health. Adequate hydration before and during physical activity helps regulate temperature and replace fluid losses, and afterward, restores complete water balance7.
The main conditions leading to a fluid deficit are high ambient temperature, high humidity, restricted fluid availability, and protective clothing that traps heat and perspiration. The consequences include decrease of blood volume, increased heart rate, hampered thermoregulation, and lowered exercise capacity.
When the environmental temperature exceeds 30°C, dehydration leads to a 2% loss of body weight and decreased endurance and skill. A 3% drop in body weight results in a decline of muscular power and strength. The more physically active a person is, the greater the water needs to maintain balance and sustain performance.
Except for people engaging in very prolonged endurance exercise (> 2-3 hours) in warm environments, there is no need to add large amounts of minerals to the fluids ingested before, during and after exercise. More water than minerals is lost during perspiration so proper fluid replacement should focus on water, not on minerals.
For short periods of exercise (60 minutes or less), there is no evidence that ingestion of carbohydrates has any effect on fatigue and performance. Evidence does show, however, that carbohydrate intake postpones fatigue and increases endurance performance for exercise lasting about 90 minutes and more8.
Healthy hydration in the workplace
Individuals performing intense physical labor in warm-hot environments can suffer from dehydration on a daily basis. Lack of hydration can adversely influence decision-making and cognitive performance and contribute to a decline in productivity, as well as increase the risk of work-related accidents9.
Education is an essential component to help workers maintain proper hydration during and after a work shift. Informing individuals, especially those who work in a hot environment, about hydration assessment, signs and dangers of dehydration, and strategies in maintaining hydration while working can reduce dehydration in the workplace. Sufficient bathroom facilities also help workers manage hydration throughout their shifts.
Workers can maintain healthy water balance by arriving on-site well-hydrated, keeping a full water bottle/container close at all times, and drinking during breaks and meals.
Sources: (7) Sawka et al. Exercise and fluid replacement.. Medicine and Science in Sports and Exercise 2007, 39(2):377-390; (8) Péronnet F. Healthy Hydration for physical activity, Nutrition Today 2010, 45 (6S): S41-S44; (9) Kenefick et al. Hydration at the work site. Journal of the American College of Nutrition 2007, 26 (5): 597S-603S Miller et al. Hydration, Hydration, Hydration. Ann Occup Hyg 2010, 54 (2): 134-136