Stay hydrated to stay big and strong in the gym

September 1, 2001


Water is critical for numerous processes in the body, and it keeps muscles full and large by filling the muscle cells. In fact, not drinking enough water can hamper your strength and limit muscle growth.

In a 2001 study by Old Dominion University (Norfolk, Virginia), researchers tested the one-rep max in the bench press of weight-trained men while they were normally hydrated and again while they were dehydrated. A 2007 study at the University of Connecticut (Storrs) tested the number of reps that weight-trained males could complete during a six-set squat workout using 80% of their 1RM under both hydrated and dehydrated conditions. Another study, published in 2008, measured subjects’ testosterone and cortisol levels after the same type of squat workout while they were normally hydrated or dehydrated. Finally, in a 2008 study by Chicago State University (Chicago, Illinois), researchers tested subjects’ leg and arm power under conditions of hydration and dehydration.

The ODU researchers reported that when dehydrated, the men’s 1RM was significantly decreased compared to their normal hydrated states. They also discovered that the leaner the subjects were, the more dehydration affected their strength. The UConn researchers found that when the subjects were dehydrated, they were unable to complete as many reps in the squat on most of the six sets, as compared to when they were normally hydrated. According to the 2008 study, dehydration significantly dropped test subjects’ testosterone levels and simultaneously boosted their cortisol levels after the workout. The CSU researchers reported that when their subjects were dehydrated, their upper-body and lower-body power was reduced by about 15% and 20%, respectively.

These results should really hit home with you, since a drop in body water as little as 1.5% of your bodyweight (three pounds for a 200-pound guy) was found to decrease strength. Your body can easily drop three pounds of water in just a few hours, depending on how much you are sweating and how much you are drinking. This could lessen your strength, power, endurance and ability to recover and grow after workouts.

To stay hydrated, Flex recommends drinking at least one gallon of water per day. Before workouts, drink 15-20 ounces of fluid (this can be from your preworkout protein shake); during workouts, drink at least 5-10 ounces every 15 minutes; and after training rehydrate with 20-32 ounces of fluid (such as from your postworkout shake).