Interstitial and arterial‐venous [K⁺] in human calf muscle during dynamic exercise: effect of ischaemia and relation to muscle pain

Abstract

Changes in the concentration of interstitial K+ surrounding skeletal muscle fibres ([K+]I) probably play some role in the regulation of cardiovascular adjustments to muscular activity, as well as in the aetiology of muscle pain and fatigue during high‐intensity exercise. However, there is very little information on the response of [K+]I to exercise in human skeletal muscle. Five young healthy subjects performed plantar flexion exercise for four 5 min periods at increasing power outputs (≈1‐6 W) with 10 min intervening recovery periods, as well as for two 5 min periods with ischaemia at ≈1 and ≈3 W. Microdialysis probes were inserted into the gastrocnemius medialis muscle of the right leg to measure [K+]I, and K+ release from the plantar flexors during and after incremental exercise was calculated from plasma flow and arterial‐venous differences for K+. Calf muscle pain was assessed using a visual analogue scale. On average, [K+]I was 4.4 mmol l−1 at rest and increased during minutes 3‐5 of incremental exercise by ≈1‐7 mmol l−1 as a positive function of power output. K+ release also increased as a function of exercise intensity, although there was a progressive increase by ≈1‐6 mmol l−1 in the [K+] gradient between the interstitium and arterial‐venous plasma. [K+]I was lower during ischaemic exercise than control exercise. In contrast to this effect of ischaemia on [K+]I, muscle pain was relatively higher during ischaemic exercise, which demonstrates that factors other than changes in [K+]I are responsible for ischaemic muscle pain. In conclusion, this study has demonstrated that during 5 min of dynamic exercise, [K+]I increases during the later period of exercise as a positive function of exercise intensity, ischaemia reduces [K+]I during rest and exercise, and the increase in [K+]I is not responsible for muscle pain during ischaemic exercise.

Potential Muscle Biomarkers of Chronic Myalgia in Humans - A Systematic Review of Microdialysis Studies

“…Green et al, however, did not find potassium related to acute ischaemic myalgia in healthy subjects (Green et al, 2000). Repetitive work in healthy subjects may increase potassium levels (Rosendal et al, 2004a), although in the present systematic review no consistent pattern of increased potassium was found in patients with chronic trapezius myalgia (Larsson et al, 2008;Rosendal et al, 2005;Sjogaard et al, 2010) (Table 1) or with chronic WAD (Table 2).…”

Lactate – a signal coordinating cell and systemic function

“…Microdialysis might allow further investigation of the Immke and McClesky (2001) hypothesis, having been used by a number of research groups (Rosdahl et al, 1993;Maclean et al, 1999;Green et al, 2000;Street et al, 2001;Rooyackers, 2005). Maclean et al (1999) confirmed that a substantial increase in interstitial lactate occurs during the transition from rest to exercise, exceeding values seen in plasma.…”

Effect of cluster multi‐diode light emitting diode therapy (LEDT) on exercise‐induced skeletal muscle fatigue and skeletal muscle recovery in humans

“…The development of skeletal muscle fatigue is characterized by a time-dependent decrease in muscle strength [1]. Several factors such as the types and intensity of exercise, the muscle groups involved, and the local physical and biochemical environment affect fatigue development, which is a complex and multifaceted process involving physiological, biomechanical, and psychological elements [2].…”