Fluid type influences acute hydration and muscle performance recovery in human subjects

Abstract

Background

Exercise and heat trigger dehydration and an increase in extracellular fluid osmolality, leading to deficits in exercise performance and thermoregulation. Evidence from previous studies supports the potential for deep-ocean mineral water to improve recovery of exercise performance post-exercise. We therefore wished to determine whether acute rehydration and muscle strength recovery was enhanced by deep-ocean mineral water following a dehydrating exercise, compared to a sports drink or mountain spring water. We hypothesized that muscle strength would decrease as a result of dehydrating exercise, and that recovery of muscle strength and hydration would depend on the type of rehydrating fluid.

Methods

Using a counterbalanced, crossover study design, female (n = 8) and male (n = 9) participants performed a dehydrating exercise protocol under heat stress until achieving 3% body mass loss. Participants rehydrated with either deep-ocean mineral water (Deep), mountain spring water (Spring), or a carbohydrate-based sports drink (Sports) at a volume equal to the volume of fluid loss. We measured relative hydration using salivary osmolality (S_osm) and muscle strength using peak torque from a leg extension maneuver.

Results

S_osm significantly increased (p < 0.0001) with loss of body mass during the dehydrating exercise protocol. Males took less time (90.0 ± 18.3 min; P < 0.0034) to reach 3% body mass loss when compared to females (127.1 ± 20.0 min). We used a mono-exponential model to fit the return of S_osm to baseline values during the rehydrating phase. Whether fitting stimulated or unstimulated S_osm, male and female participants receiving Deep as the hydrating fluid exhibited the most rapid return to baseline S_osm (p < 0.0001) regardless of the fit parameter. Males compared to females generated more peak torque (p = 0.0005) at baseline (308.3 ± 56.7 Nm vs 172.8 ± 40.8 Nm, respectively) and immediately following 3% body mass loss (276.3 ± 39.5 Nm vs 153.5 ± 35.9 Nm). Participants experienced a loss. We also identified a significant effect of rehydrating fluid and sex on post-rehydration peak torque (p < 0.0117).

Conclusion

We conclude that deep-ocean mineral water positively affected hydration recovery after dehydrating exercise, and that it may also be beneficial for muscle strength recovery, although this, as well as the influence of sex, needs to be further examined by future research.

Trial registration

clincialtrials.gov PRS, NCT02486224. Registered 08 June 2015.

Keywords:

• Dehydration
• Exercise
• Deep sea water
• Humans
• Sweat

Acknowledgements

We would like to thank Kona Deep®™ for providing the deep-ocean mineral water.

Funding

This work was supported by an Independent Scientist Award (K02 HL105799) from the NIH and a grant from the Sarver Heart Center awarded to J.P. Konhilas. Support was provided by a Short Term Institutional Training Grant (T35HL007479–35) to E. Hines.

Availability of data and materials

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Authors’ contributions

PRH oversaw completion of the exercise protocols, collected and analyzed participant data and saliva samples, and was the major contributor in writing the manuscript. DAK co-designed the study, supervised experiments in the exercise lab, and was a contributor in writing and revising the manuscript. EC oversaw completion of the exercise protocols, collected, analyzed, and interpreted participant data and saliva samples. SNW assisted with the exercise experiments, collected and analyzed saliva samples, and contributed to the revision of the manuscript. EH significantly contributed to the interpretation of the data, and the drafting and revision of the manuscript. MPK significantly contributed to the interpretation of the data, and the drafting and revision of the manuscript. ZIK acted as the responsible physician for the study, and significantly contributed to the drafting and revision of the manuscript. JPK co-designed the study, and supervised all research and statistical analysis of the data. All authors read and approved the final manuscript.

Ethics approval and consent to participate

All participants provided consent under protocols adhering to guidelines approved by the Institutional Review Board at the University of Arizona and in accordance with the Declaration of Helsinki.

Consent for publication

Not applicable.

Competing interests

1. Kona Deep®™ provided the deep-ocean mineral water.

2. The results of the present study do not constitute endorsement by ACSM

3. The results of the study are presented clearly, honestly, and without fabrication, falsification, or inappropriate data manipulation.

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