Hydration Status Affects Muscle Function in Middle-Aged Adults

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Researchers in Spain have published a study highlighting the crucial role of hydration in muscle function, particularly in middle-aged adults. The investigation aimed to assess the effects of 12-hour overnight fasting on muscle function in individuals aged 35-65 years. The findings revealed a significant correlation between hydration status and muscle strength, work, and power in both men and women. Notably, the study found that muscle function improved after water intake, especially in women. However, the effects were observed to be more pronounced in individuals aged 45 years or older.

Key Takeaways:

  • The study involved 59 volunteers, 47 years old on average, with 81.4% being women.
  • The research found a positive correlation between hydration status and muscle function in both men and women.
  • In women, the intracellular water to fat-free mass ratio and phase angle were positively correlated with flexion and extension strength and work.
  • Muscle function improved significantly after water intake in women, with increased flexion strength, work, and power.
  • However, in men, no changes in muscle function were observed after water intake.
  • The effects of hydration on muscle function were more pronounced in individuals aged 45 years or older.
  • The research concluded that more studies are required to understand the influence of hydration on muscle function and the underlying mechanisms.

Statistics:

  • 59 volunteers participated in the study, with an average age of 47 years.
  • 81.4% of the participants were women.
  • The study found significant differences in flexion strength (58.7 vs 61.8 N, p = 0.004) and work (269.0 vs 284.0 J, p = 0.003) in individuals aged 45 years or older after water intake.
  • The participants' hydration status was assessed by bioelectrical impedance analysis (BIA) and muscle function by an isokinetic test.

Sources:

  • Lorenzo, I., et al. "Effect of small variations in hydration status due to 12-hour fasting on lower limb muscle function in middle-aged adults." Physical Activity and Nutrition, 2025;29(3):33-39.
  • NewsRx. "Reports from Isabel Lorenzo et al Highlight Recent Findings in Physical Activity and Nutrition (Effect of small variations in hydration status due to 12-hour fasting on lower limb muscle function in middle-aged adults)." Health & Medicine Week, October 31, 2025; p 5076.