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Biochemical Changes in Response to Intensive Resistance Exercise Training in the Elderly

Background: It is assumed that low-grade inflammation, characterized by increased circulating IL-6 and TNF-α, is related to the development of sarcopenia. Physical exercise, especially high intensity resistance training, has been shown to be effective in restoring the strength deficit in the elderly. Intensive exercise is accompanied by significant release of IL-6 and TNF-α into the blood circulation, but does not result in muscle wasting. Exercise-induced changes in heat-shock protein (Hsp), responsible for cellular protection during stressful situations, might interfere with the acute phase reaction and muscle adaptation. Objective: To investigate if intensive strength training in elderly persons induces changes in Hsp70 expression, and if these changes are related to changes in the acute phase reaction or muscle adaptation. Methods: 31 elderly persons (aged 68.4 ± 5.4 years) performed 6 weeks’ intensive strength training. At baseline and after 6 weeks, muscle strength, functional performance (physical activity profile, 6-min walk, 30- second chair stand, grip strength, chair sit & reach and back scratch), linear isokinetic leg extension, circulating IL-6, TNF-α, IL-10 and TGF-β, and Hsp70 in monocytes (M) and lymphocytes (L) immediately after sampling (IAS), after incubation at 37 and 42°C were determined. In 12 participants, cytokines were determined in untrained and trained conditions before and after a single training session. Results: After 6 weeks’ training, muscle strength and functional performance improved significantly, together with decreased Hsp70 IAS and Hsp70 37°C and increased Hsp70 42°C (all p < 0.05). Strength gains correlated positively with baseline Hsp70 37°C and training-induced changes of Hsp70 42°C in M and L. In an untrained condition, training induced an increase of IL-6 (p < 0.05) and a tendency of IL-10 to decrease (p = 0.06). In a trained condition the decrease of IL-10 disappeared. Baseline physical activity and 6-min walk distance correlated negatively with circulating IL-6 (p < 0.05); except for a negative correlation between TGF-β and Hsp70 37°C L (p < 0.05), no significant relationships were found between cytokines and Hsp70. After the training program, Hsp70 37°C was negatively related to circulating TNF-α, IL-10 and TGF-β. Conclusion: Strength training in the elderly induces changes in Hsp70 expression, associated to strength gains and circulating cytokines.