PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Physical exercise”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 883 records · Page 49Linked to original sources
PubMed1987

Changes in the helper and suppressor lymphocytes in human peripheral blood following maximal physical exercise.

Lymphocyte subpopulations and Con A activated suppressors were measured before, immediately after maximal physical effort on bicycle ergometer and after two-hour recovery. The investigations were performed on healthy male volunteers, trained male and female cyclist, nearly at the same age. The measured parameters of maximal effort were comparable in all investigated groups. The significant increase in T8+ (suppressor cytotoxic) cells and moderate increase in T4+ (helper inducer) cells was observed after maximal physical effort; these changes were accompanied by a significant diminution of a T4+/T8+ ratio. Two-hour recovery resulted in the normalization of the investigated parameters. The functional test based on Con A-induced suppressor activity has revealed the divergence, a decrease in Con A-induced suppressor cell activity was noted after maximal effort.

Adolescent↗
PubMedDate not supplied

The effects of physical exercise at high altitude on adrenocortical function in humans.

The combined effects of sustained physical activity and hypoxia on adrenocortical function were investigated in 14 healthy volunteers, 8 males and 6 females (mean age 40.9 +/- 3.3 years), during a scientific expedition in the Himalayas. Plasma cortisol levels were measured in all subjects in basal conditions and after the administration of 1 mg dexamethasone (DXM) p.o. The study was performed before and after 15 days of intense trekking (Leh, altitude 3700 m). While on both occasions subjects retained their cortisol circadian fluctuations, basal and post-DXM cortisol levels at high altitude were significantly higher (p < 0.005 and p < 0.0005) than before climbing. Cortisol suppression was noted in all cases at low altitude, whereas 4 out of the 14 subjects did not show reduced hormone levels after 15 days of trekking. Moreover, nonsuppressor subjects had significantly higher (p < 0.05) baseline cortisol levels than suppressors. Basal and post-DXM hormone levels were found to be unrelated to age and sex of subjects. The present data further suggest that sustained physical activity at altitude activates adrenocortical function in normal individuals; however, in 30% of subjects DXM-induced cortisol suppression does not occur. To explain the latter observation, the concomitant role of hypoxia (and/or other environmental changes) and the subjective perception of physical stressors should be taken into account.

Adrenal Cortex↗
PubMed1992

Plasma hormones and physical exercise.

The analysis of published data allowed us to establish main traits of blood hormone responses to exercises: There are stable changes in hormone levels that are common to all persons, as well as changes which are characterized by a polyphasic pattern and exhibiting inter-individual variability. By the response rate it is possible to discriminate fast responses, responses of a modest rate and delayed responses. Accordingly, mechanisms for a rapid and for a delayed activation exist. The changes mediated through the mechanism for a rapid activation depend on the intensity of exercise, revealing the threshold intensity for endocrine response. When a certain amount of exercise is done, the hormonal responses are triggered despite the under-threshold intensity of exercise. Consequently, a threshold duration of exercise also exists. Through training the threshold intensity of exercise increases and the functional capacities of the endocrine systems augment. The former results in the disappearance of hormonal responses during exercise intensity which was previously above the threshold. The latter makes it possible to achieve especially pronounced and long-lasting hormonal changes during extreme exercises. Emotional states as well as environmental conditions, and carbohydrate supply modulate the hormonal changes in exercise.

Exercise↗
PubMed1989

Influence of prolonged physical exercise on plasma volume, plasma proteins, electrolytes, and fluid-regulating hormones.

Fluid-regulating hormones [arginine vasopressin (AVP) and aldosterone] as well as electrolytes, plasma volume (PV), and plasma proteins were studied in 16 well-trained male amateur runners (mean age 31.8 years) before t0), immediately after (t1), and 60 min (t2) and 22 h (t3) after a marathon run. Immediately after the run PV was significantly decreased by 12.1%, whereas the concentration of plasma proteins increased by 13.9%, sodium by 5.8 mMol.l-1, and potassium by 0.58 mMol.l-1, respectively. Aldosterone increased by 1089 pg/ml and AVP by 9.0 pg/ml. PV was significantly increased 22 h after the run by 10.6% (P less than 0.001) and plasma proteins were increased by 1.0% (P greater than 0.05), whereas aldosterone and AVP as well as electrolytes returned to control values. At t1, and particularly at t2 and t3, the total plasma protein concentration increased much more than could have been expected from changes of PV. It is suggested that this phenomenon was caused by an influx of proteins into the vascular space. This might also be the reason for the expanded PV especially in the longer recovery period at t3. The volume-regulating hormones (AVP and aldosterone) may play an important role during and immediately after the run but not in the longer recovery period (t2 and t3).

Adolescent↗