title: Impact of Mild Hypohydration on Muscle Endurance, Power, and Strength in Healthy, Active Older Men.
abstract: Goulet, EDB, Mélançon, MO, Lafrenière, D, Paquin, J, Maltais, M, and Morais, JA. Impact of mild hypohydration on muscle endurance, power, and strength in healthy, active older men. J Strength Cond Res 32(12): 3414-3424, 2018-Under particular circumstances older persons may be vulnerable to developing mild chronic hypohydration. In young adults, hypohydration has been shown to impair muscle endurance, power and strength. Muscle performance declines with aging, a condition known as dynapenia. How hypohydration impacts muscle performance in older persons remains unclear. In this study, we examined this question, believing it may identify a factor exacerbating dynapenia. One-hour after having been passively exposed to heat where either a body mass loss of 1% was induced or euhydration maintained with fluid ingestion, 8 healthy, active older men (age: 68 ± 5 years) completed an exercise testing session where indices of muscle strength (30-second chair stand, grip strength, maximal isometric seated leg-press extension), endurance (seated leg-curl flexion + seated leg-press extension to exhaustion at 60% of 1 repetition maximum), and power (30-second Wingate test) were assessed. Gastrointestinal temperature before exercise testing was not significantly different from that measured before heat exposure with neither hydration regimen. Magnitude-based inferential statistics indicate that from a clinical perspective, the effect of hypohydration on 30-second chair stand (-1.0 ± 4.4%) is possibly harmful, for grip strength (-2.4 ± 4.1%), lower limbs endurance (-7.5 ± 11.2%), and anaerobic power (-3.9 ± 4.3%) likely detrimental, and unclear with respect to maximal isometric lower limb strength. Maintaining adequate hydration in older men is important, since hypohydration of only 1% body mass could impede muscle endurance, power and strength and, consequently, worsen the impact of dynapenia.
authors.affiliation: Department of Kinanthropology, Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, Québec, Canada.|Research Center on Aging, University of Sherbrooke, Sherbrooke, Québec, Canada.
authors.forename: Eric D B
authors.initials: EDB
authors.lastname: Goulet
authors.affiliation: School of Readaptation, Faculty of Medicine and Health Sciences, University of Sherbrooke, Québec, Canada.
authors.forename: Michel O
authors.initials: MO
authors.lastname: Mélançon
authors.affiliation: Department of Kinanthropology, Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, Québec, Canada.
authors.forename: David
authors.initials: D
authors.lastname: Lafrenière
authors.affiliation: Department of Kinanthropology, Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, Québec, Canada.
authors.forename: Jasmine
authors.initials: J
authors.lastname: Paquin
authors.affiliation: Research Center on Aging, University of Sherbrooke, Sherbrooke, Québec, Canada.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Maltais
authors.affiliation: Division of Geriatric Medicine, Faculty of Medicine, McGill University, Montreal, Québec, Canada.
authors.forename: José A
authors.initials: JA
authors.lastname: Morais
mesh_terms: D000368:Aged; D001794:Blood Pressure; D001831:Body Temperature; D005080:Exercise Test; D006339:Heart Rate; D006358:Hot Temperature; D006801:Humans; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000502:physiology*; D000074267:Organism Hydration Status; D010807:Physical Endurance; D014867:Water
chemical_list: D014867:Water