1Gazi University, School of Physical Education and Sport, Ankara, Turkey
2Ataturk University, School of Physical Education and Sports, Erzurum, Turkey
Plasma Growth Hormone and Prolactin Levels in Healthy Sedentary Young Men after Short-Term Endurance Training under Hot Environment
Pituitary hormones play an important role energy expenditure and body temperature regulation during exercise. The aim of the stu¬dy was to investigate the effect of two different endurance training in ambient temperature (30.76 ± 1.71oC and 57.92 ± 5.80% r.h.) on plasma growth hormone (GH) and prolactin (PRL) levels in non-trained healthy subjects. Twenty-four untrained healthy men participated in an 8-wk progressive two different endurance-training program. Subjects were divided into two groups: an in¬ter¬val running group (IR), and continuous running group (CR). Both groups were performed 3 days/wk. Growth hormone, PRL and VO2max levels were assessed at the beginning and the end of the training period. Body temperature (TB) was also measured at the be¬ginning and immediately after each training. The exercise type affected plasma PRL (8.52 vs. 6.50 ng/ml IR and CT groups, P < 0.02) but did not alter plasma GH levels (0.95 vs 0.63 ng/ml IR and CT groups, P>0.38). Plasma GH level at the end of training pro¬gram increased from 0.42 to 1.48 ng/ml and 0.58 to 0.67 ng/ml for IR and CR groups. Expectedly, both training types increased TB, at a greater rate for IR group than CR group. In conclusion, an 8-wk regular exercise result in an increase in plasma PRL level, with¬out altering plasma GH level, which accompanied by elevated body temperature, regardless of the individual’s sporting rou¬ti¬ne. These suggest that untrained individuals could benefit from a regular exercise program as much as those doing the routine sport.
GH, PRL, hot temperature, endurance training
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