The promise of growth hormone in sport: doped or duped

Abstract

Skeletal muscle is a target tissue of GH. Based on its anabolic properties, it is widely accepted that GH enhances muscle performance in sports. Athletic performance depends on muscle strength and the energy required to power muscle function. The energy required to power muscle function is derived from a continuum of anaerobic and aerobic sources. Molecular and functional studies provide evidence that in muscle GH stimulates the anaerobic and suppresses the aerobic energy system, in turn affecting power-based functional measures in a time-dependent manner. In recreational athletes, GH improves anaerobic capacity but has not been proven to significantly enhance muscle strength, power, or maximum rate of oxygen consumption. GH appears likely to selectively benefit sprint events and not physical performance that depends on strength and endurance.

Evaluation of Sleep Parameters and Sleep Staging (Slow Wave Sleep) in Athletes by Fitbit Alta HR, a Consumer Sleep Tracking Device

“…Consumer devices continually update their hardware and software systems to improve sleep tracking performance 11 , 13 , 14 . In particular, the ratio of N3 sleep per TST, which defines the quality of sleep, and the percentage of N3 in sleep onset and initial REM sleep, which is involved in the recovery of athlete’s physical strength, 19 are essential in terms of condition management. FBA, which is equal to EEG in detecting this part, is a handy tool for athletes to manage their condition.…”

“…Additionally, we assessed the percentage of N3 sleep during the interval from sleep onset to initial rapid eye movement (REM) sleep (ie, percentage of N3 sleep in initial non-REM sleep) because this is related to the secretion of growth hormone, which is essential for athletes. 19 Arousal index (ArI) was calculated as the number of microarousals per hour of sleep.…”

The relationship between body composition and sleep architecture in athletes

“…For sleep stages, the percentages of rapid eye movement (REM) sleep (ie, stage R) and slow-wave sleep (ie, stage N3) per TST were determined. In addition, we assessed the percentage of N3 sleep during the interval from sleep onset to initial REM sleep (ie, percentage of N3 sleep in initial non-REM sleep) because this is important for athletes in terms of growth hormone secretion [16]. Arousal index was calculated as the number of microarousals per hour of sleep.…”

Annual banned‐substance review: Analytical approaches in human sports drug testing 2019/2020

“…Growth hormone (GH) and its natural variants as well as GH's main mediator insulin‐like growth factor‐I (IGF‐I) are critical for a variety of physiological processes, and their misuse in sports has been suspected and/or proven at numerous occasions, despite well‐established health risks associated with the non‐therapeutic use 115 . The use of GH on its own is not considered to contribute to enhanced endurance performance, 116 and yet it has been purportedly been misused in combination with EPO. Marchand et al conducted a single‐blinded administration study with combined EPO and GH microdoses to assess both the traceability of GH misuse in serum and potential effects on physiological parameters indicative for a person's athletic performance 117 .…”