Circulating hormone and cytokine response to low-load resistance training with blood flow restriction in older men.

It has been suggested that circulating hormones and cytokines are important in the adaptive response to low-load resistance training (LLRT) with blood flow restriction (BFR); however, their response following this type of training in older men is unclear. Seven healthy older men (age 71.0 ± 6.5 year, height 1.77 ± 0.05 m, body mass 80.0 ± 7.5 kg; mean ± SD) performed five sets of unilateral LLRT knee extensions (20 % 1-RM) of both limbs, with or without BFR in a counterbalanced order. For the BFR condition, a pressure cuff was applied on the upper thigh and inflated to ~110 mmHg. Venous blood samples were taken at rest and 30-, 60- and 120-min post-exercise and measured for plasma concentrations of growth hormone (GH), insulin-like growth factor 1 (IGF-1), vascular endothelial growth factor (VEGF), cortisol and interleukin-6 (IL-6). GH increased (P < 0.05) from rest to 30-min post-exercise and was greater (P < 0.05) during LLRT with BFR than without. VEGF was significantly (P < 0.05) elevated from resting levels at 30-, 60- and 120-min post-exercise following LLRT with BFR with no change seen following LLRT without BFR. IL-6 increased (P < 0.05) from 30- to 60-min post-exercise and remained elevated at 120-min post-exercise in both conditions. Cortisol and IGF-1 were unaffected following exercise. In conclusion, a single bout of LLRT with BFR increases the circulating concentrations of GH and VEGF in older men and may explain the skeletal muscle and peripheral vascular adaptations observed following training with BFR.