Influences of carbohydrate plus amino acid supplementation on differing exercise intensity adaptations in older persons: skeletal muscle and endocrine responses

Abstract

Losses in physiological function in healthy ageing occur partly as a consequence of reduced protein intake and partly as a consequence of less than 30-min/day of moderate to vigorous physical activity. The current study aimed to compare the effects of two different intensities of resistance training in healthy older adults, whose habitual dietary intake was supplemented with carbohydrate and amino acid preparations. We hypothesised that although intensive exercise with appropriate carbohydrate and amino acid supplementation would result in the most profound impact on in vivo markers of healthy physiologic and endocrine functions in previously sedentary older individuals, the effectiveness of the less intense exercise prescription with supplementation would also result in beneficial adaptations over and above findings of previous studies on low intensity exercise alone. Twenty-nine older adults (out of 32) completed the study after being randomly assigned to low (SUP_LowR, i.e., ∼40% 1RM; n=16) versus high resistance training (SUP_HighR, i.e., ∼80% 1RM; n=13) for 12 weeks. A carbohydrate supplement was ingested immediately before and during every exercise session and an amino acid cocktail was ingested post-exercise. Neither intervention significantly impacted upon body composition assessed using: Body mass index, waist/hip ratio and bioelectric impedance. Muscle strength increased similarly in the two groups with the SUP_HighR protocol showing 46±8%, 10.8±4.4% and 26.9± 4.9% (P<0.01) improvements in 1-RM strength, unilateral and bilateral knee extension torque, respectively, compared with 39±2%, 9.4±3.7% and 29.5± 8.2% (P<0.01) increments in the same measures in the SUP_LowR group. Lean muscle thickness however, showed a greater benefit of the SUP_LowR protocol (8.7±3.9% increase, P<0.05) compared with the SUP_HighR protocol, which elicited no significant change. In terms of functional abilities, only the standing-from-lying (SFL) test exhibited an improvement in rate in the SUP_HighR group (−11.4%, P< 0.05). The SUP_LowR group, on the other hand, showed significant improvements in the get-up-andgo (−8.7±3.6%, P<0.05), the SFL (−4.7% change, P=0.05) and the 6-min walk (7.2±2.2% increase in distance covered, P<0.01) tests. Following overnight AGE (2010) fasting, serum levels of glucose changed significantly (−13±4.7% decrease, P<0.01) in SUP_LowR. Serum levels of insulin (−25± 5.3% decrease, P=0.05), neuropeptide Y (−24±15.3% decrease, P=0.02), and IGFBP-3 (−11±6.6% decrease, P=0.03), changed significantly in SUP_HighR. Circulating levels of interleukin-6, tumour necrosis factor-alpha and insulin-like growth factor 1 did not alter significantly in either intervention group. These data suggest that whilst both interventions were beneficial in older persons, the end targets as well as metabolic and hormonal adaptations are different. The supplementation plus low exercise regimen tended to impact on muscle hypertrophy combined with increased habitual function. Supplementation plus high-intensity exercise ...

Dietary protein intake and subsequent falls in older men and women: The Framingham study

“…Falls were reported by participants using a validated questionnaire [8] at both the baseline exam 1988–1989 and the follow-up exam in 1990–1991. Trained clinic staff asked participants, “In the past year have you accidentally fallen and hit the floor or ground?” and “If yes, how many times did you fall in the past year”.…”

“…While approximately half of all falls result in a minor injury [5], up to 10 percent result in a serious injury such as subdural hematoma, head trauma, or fracture [5–7]. Although only one percent of falls result in hip fracture [8], nearly all of hip fractures may be attributed to falls [9]. Falls can also lead to a decline in social and physical activities [10] and loss of independence [11], particularly amongst older adults.…”

Dietary protein intake and subsequent falls in older men and women: The Framingham study

“…Falls were reported by participants using a validated questionnaire [8] at both the baseline exam 1988-1989 and the follow-up exam in 1990-1991. Trained clinic staff asked participants, "In the past year have you accidentally fallen and hit the floor or ground?"…”

“…While approximately half of all falls result in a minor injury [5], up to 10 percent result in a serious injury such as subdural hematoma, head trauma, or fracture [5][6][7]. Although only one percent of falls result in hip fracture [8], nearly all of hip fractures may be attributed to falls [9]. Falls can also lead to a decline in social and physical activities [10] and loss of independence [11], particularly amongst older adults.…”

Necesidades proteicas de los deportistas y pautas diétetico-nutricionales para la ganancia de masa muscular

“…En estudios realizados con ancianos desentrenados, se ha observado que la ingesta de un suplemento proteico que suponía el 50% de la IR de proteínas, acompañado de un programa de entrenamiento de fuerza durante 3 meses, aumentaba el área muscular y la excreción de creatinina en la orina. Por otro lado, no se observaron aumentos signi cativos en la fuerza, pero este hecho no tiene por qué estar relacionado con el aumento de la hipertro a muscular 90,91 . De todos modos, existen pocos estudios en relación con los requerimientos diarios de proteínas de los ancianos 56,87,92 o los niños y adolescentes 55,86 que realizan ejercicio físico de forma regular 38 .…”