Testosterone, Cortisol, and Creatine Kinase Levels in Male Distance Runners During Reduced Training

Abstract

The purpose of this study was to examine if reduced training would reestablish normal testosterone, cortisol, and creatine kinase (CK) levels in male distance runners. Ten male runners (mean +/- SE) age 32.0 +/- 2.6 yrs, body fat 9.6 +/- 1.0%, VO2max 61.8 +/- 1.1 ml/kg/min) were monitored during 4 weeks of normal training (baseline training, BT) and 3 weeks of reduced training (RT). During BT running distance averaged 81 +/- 5 km/week, 6 days/week. During RT the runners reduced weekly training volume by 70% of BT to 24 +/- 2 km/week and training frequency to 5 days/week. Weekly resting blood samples were obtained between 0600-0900 hrs after an overnight fast. During BT resting total testosterone levels averaged 5.10 +/- 0.21 ng/ml, which is within the low ranges previously reported in male distance runners. Testosterone levels were not affected by RT (avg of 5.38 +/- 0.31 ng/ml). Cortisol levels were in the high range of normal during BT (23.61 +/- 1.18 ug/dl) and were not altered with RT (avg of 23.14 +/- 1.56 ug/dl). Creatine kinase was elevated (168 +/- 15 U/L) during BT and was significantly reduced (P less than 0.001) at weeks 1-3 of RT (avg of 99 +/- 9 U/L). These results suggest that normally training male runners have low resting total testosterone levels and cortisol levels in the high-normal range. Resting testosterone and cortisol were not responsive to the training reduction. Creatine kinase appears to be sensitive to relative changes in training.

Effect of altitude training on serum creatine kinase activity and serum cortisol concentration in triathletes

“…We further speculated that the additional increases in serum CK activity at ALT 2 (7 days after arriving at altitude), ALT 3 (18 days after arriving at altitude) and ALT 4 (24±36 h prior to the end of the 5-week altitude camp) were due to the combined eect of hypobaric hypoxia and training, given that training intensity and/or volume increased progressively throughout the 5-week altitude training camp (Table 3). Serum CK values from ALT 2 through ALT 4 were similar to those reported in studies conducted at sea level involving well-trained male distance runners engaged in habitual endurance training, which consisted of running 81 km per week, 6 days per week (Houmard et al 1990). Despite the fact that serum CK activity was signi®cantly elevated throughout the duration of the 5-week altitude training period, our subjects were able to train very eectively and did not display any signs of being overworked, overtrained or injured.…”

“…In addition, Stray-Gundersen et al (1986) observed a signi®-cant increase in serum CK activity [282 (25) U á l A1 ] in the runners following 2 weeks of increased training (additional hard interval sessions), and a decrease in serum CK activity [165 (16) U á l A1 ] after resumption of normal training. Similar ®ndings were reported by Houmard et al (1990) who observed elevated serum CK activity [168 (15) U á l A1 ] in trained male distance runners during 4 weeks of increased training (81 km per week, 6 days per week), and a decrease in serum CK activity [99 (9) U á l A1 ] during 3 weeks of reduced training (24 km per week, 6 days per week). Apple and McGue (1983) reported that serum CK activity was 12 times higher than clinically normal values in runners who regularly trained 80±160 km per week, while Dressendorfer and Wade (1983) observed elevated serum CK activity (400±500 U á l A1 ) in endurance athletes running approximately 28 km per day for 20 days in the 500-km Great Hawaiian Footrace.…”

Effect of consecutive aerobic and resistance exercise on cortisol, immunoglobulin A, and creatine kinase responses in male students

“…Therefore, serum CK activity has been theoretically expected to be useful as a marker in exercise physiology and sports medicine for the detection of muscle injury and overwork [13]. However, previous studies on CK release have not clearly demonstrated its value as a marker for these states [27].…”

Effect of Consecutive Aerobic and Resistance Exercise on Cortisol,creatine Kinase and Immunoglobulin a Responses in Male Athletes

“…However, while some studies have reported no acute changes in cortisol secretion in response to resistance exercise (Dohi et Creatine kinase (CK) is found predominantly in muscle and is released into circulation during muscular lesions. Therefore, serum CK activity has been theoretically expected to be useful as a marker in exercise physiology and sports medicine for the detection of muscle injury and overwork (Houmard et al 1990). However, previous studies on CK release have not clearly demonstrated its value as a marker for these states (Newham et al, 1987).…”

“…It is generally recognized that IgA, due to its dominance in the immune system of mucous membranes, is the first line of defense against harmful environmental factors. The secretion and composition of saliva depends on the activity of the sympathetic and parasympathetic nervous systems (Houmard et al, 1990). Physical activity, stimulating the autonomous nervous system, may reduce the amount of saliva and/or inhibit its secretion.…”