New Study Shows That Dehydration is Detrimental to Resistance Exercise Adaptations

Share Article

Developing lean body mass and achieving body fat loss may be more difficult if you are dehydrated. Find out why.

A brand new study in the Journal of Applied Physiology reveals that being dehydrated can significantly impair the strength and body fat loss results you might be looking for from a resistance exercise program.

The researchers from this brand new study looked at 7 healthy, resistance-trained males and subjected them to 6 sets of squats (at 80% of 1RM) in three different hydrated states: euhydrated (normal), dehydrated (-2.5% of body mass), very dehydrated (-5% of body mass).

The subjects were asked to complete as many reps (over the 6 sets) as they previously had completed during their pre-study test.

The Three Main Findings of The Study Were That:

1) dehydration significantly increases circulating concentrations of stress hormones cortisol and norepinephrine,

2) dehydration attenuates the testosterone response to exercise, and

3) dehydration alters carbohydrate and fat metabolism

These are significant findings if resistance exercise is an integral part of your fitness regimen (and it should be!) because it highlights the importance of remaining adequately hydrated to get the most from your strength training workouts.

Several other studies have shown the negative impact of dehydration on endurance exercise but this study is one of the first to investigate the importance of exercise hydration status for resistance training individuals.

Discussion of Findings:
The novel results from this study show that dehydration causes an increase in catabolic stress hormones such as cortisol and norepinephrine. These are hormones that are released during stressful conditions and do not favour the maintenance or building of lean body mass. Instead, as catabolic stress hormones, they are known to "break down" reserves in the body for immediate energy needs.

The dehydrated exercise states likely stimulated these catabolic hormones by increasing the body's core temperature and cardiovascular demand resulting from a decreased blood plasma volume. Again, conditions such as an elevated core body temperature and lower blood plasma volume result from having less water in the body and represent a state of "stress". Not a good thing if you want to preserve your lean body mass.

Since, cortisol became elevated during the dehydrated state, there was also a significant rise in blood glucose. Remember, cortisol breaks down carboydrate reserves (ie. glycogen), leading to a rise in blood sugar. Subsequently, this study also found that there was a rise in insulin (to remove the excess glucose from the blood). This rise in insulin (an anabolic hormone) is known to inhibit fat breakdown.

Does Dehydration Eat Away at Lean Body Mass?
One of the main ways that our muscles get stronger (and larger) is via an increased release of testosterone after resistance training. However, the current study demonstrates that resistance exercise in a dehydrated state attenuates the resistance exercise-induced increases in testosterone; therefore, reducing the efficacy of strength workouts for strength and/or development of lean body mass.

In Conclusion
The results of this new and novel research indicate that dehydration produces a less beneficial post-exercise hormonal milieu by increasing catabolism (break down) and potentially decreasing anabolism (build up). Therefore, these findings suggest that if you routinely complete resistance exercises in a dehydrated state you are probably compromising the strength and body fat loss results you may have otherwise achieved!

Visit to learn how make resistance exercise work for you!



Share article on social media or email:

View article via:

Pdf Print

Contact Author

Visit website