Journal Title (Medline/Pubmed accepted abbreviation): Eur. J. Appl. Physiol.
First page: 2051-2061
doi (if applicable): 10.1007/s00421-011-1831-5
Background: Ingestion of carbohydrates during endurance events provides fuel and improves endurance in events of moderate temperature. However, these benefits are not always seen when the endurance event is in the heat. Some studies have shown a benefit of adding protein to carbohydrate/electrolyte sports beverages because of improved recovery, additional energy availability, improved temperature regulation, improved fluid retention, and/or other mechanisms.
Hypothesis: A protein + carbohydrate supplement will improve temperature regulation, reduce muscle damage, and ultimately improve performance compared to a carbohydrate supplement during a multi-day cycling race in a hot environment.
Subjects: Twenty-eight trained mountain bikers, age 30-32, competing in the 2007 TransAlp Challenge mountain bike race.
Experimental design: random, placebo-controlled, double-blind design
Treatments : CHO: 76 g carbohydrate, 460 mg sodium, 120 mg potassium per liter
CHO + PRO: 72 g CHO, 4 g whey protein, 648 mg sodium, 170 mg potassium per liter
All supplements were consumed ad libitum (as desired).
Protocol : On the day before the race, the subjects were evaluated for VO2maxand assigned to a treatment group, equally distributing gender and fitness levels between groups. The race was 8 days long. On all days of the race, the subjects were weighed before breakfast and provided a urine sample. Temperature was taken and a fingertip blood sample was acquired at selected time points throughout the race. Blood samples were assessed for glucose and creatine kinase.
Addition of protein to carbohydrate sport beverages can improve performance in long, duration, hot weather endurance events. The mechanism of this benefit is not known, but the additional protein could help regulate body temperature, provide additional energy, and/or help with fluid retention.