Staying hydrated is important not only for health reasons and for keeping your muscles full, but also for muscle strength.
Several clinical studies have looked into the effects of dehydration on muscle strength. One study performed at Old Dominion University (Virginia) tested weight-trained men’s bench press one-rep max when they were normally hydrated versus when they were dehydrated. A University of Connecticut (Storrs) study compared the total number of reps that weight-trained men completed during six sets of squats using 80% of their 1RM when they were either normally hydrated or dehydrated. And a 2008 study by Chicago State University researchers tested the muscle power of subjects when they were normally hydrated and when they were dehydrated.
The Old Dominion study found that when the subjects were dehydrated, their 1RM was about 10% less than when they were normally hydrated. They also found that the leaner the subjects were, the more that dehydration reduced their strength. The UConn scientists reported that when the subjects were dehydrated, they completed fewer reps on the squat during most of the 6 sets than they did when they were normally hydrated. The Chicago State researchers found that when the subjects were dehydrated, their muscle power was reduced by about 20% compared to when they were normally hydrated.
If you don’t drink enough fluids, you could run the risk of having less muscle strength, power and endurance. All of this could have a negative impact on your muscle growth.
Most bodybuilders think that dehydration is something that only marathon runners need to worry about. Not so. The research showing that dehydration decreased strength by 10% was done with subjects losing just 1.5% of their bodyweight. That’s just over 2 pounds of bodyweight for a 180-pound guy. Does your weight fluctuate from day to day by a couple of pounds? You’d better believe it. And when it’s down by just that little amount, your strength may drop by as much as 10%. Think of it this way: staying well hydrated could increase your strength immediately by 10%! To stay hydrated, drink about 1 gallon of water per day.