Aging and assessment of physiological strain during exercise-heat stress

2002 ◽  
Vol 282 (4) ◽  
pp. R1063-R1069 ◽  
Author(s):  
Daniel S. Moran ◽  
W. Larry Kenney ◽  
Jane M. Pierzga ◽  
Kent B. Pandolf
Keyword(s):  
Heat Stress ◽  
Hormone Replacement Therapy ◽  
Replacement Therapy ◽  
Aerobic Training ◽  
Aerobic Power ◽  
Hormone Replacement ◽  
Cycle Ergometer ◽  
Maximal Aerobic Power ◽  
Physiological Strain ◽  
The Third

The purpose of this study was to evaluate the physiological strain index (PSI) for different age groups during exercise-heat stress (EHS). PSI was applied to three different databases. First, from young and middle-age men (21 ± 2 and 46 ± 5 yr, respectively) matched ( n = 9 each, P > 0.05) for maximal aerobic power. Subjects were heat acclimated by daily treadmill walking for two 50-min bouts separated by 10-min rest for 10 days in a hot-dry environment [49°C, 20% relative humidity (RH)]. The second database involved a group ( n = 8) of young (YA) and a group ( n = 7) of older (OA) men (26 ± 1 and 69 ± 1 yr, respectively) who underwent 16 wk of aerobic training and two control groups ( n = 7 each) who were matched for age to YA and OA. These four groups performed EHS at 36°C, 40% RH on a cycle ergometer for 60 min at 60% maximal aerobic power before and after training. The third database was obtained from three groups of postmenopausal women and a group of 10 men. Two groups of women ( n = 8 each) were undergoing hormone replacement therapy, estrogen or estrogen plus progesterone, and the third group ( n = 9) received no hormone replacement. Subjects were over 50 yr and performed the same EHS: exercising at 36°C, 40% RH on a cycle ergometer for 60 min. PSI assessed the strain for all three databases and reported differences were significant at P < 0.05. This index rated the strain in rank order, whereas the postacclimation and posttraining groups were assessed as having less strain than the preacclimation and pretraining groups. Furthermore, middle-aged women on estrogen replacement therapy had less strain than estrogen + progesterone and no hormone therapy. PSI evaluation was extended for men and women of different ages (50–70 yr) during acute EHS, heat acclimation, after aerobic training, and inclusive of women undergoing hormone replacement therapy.

scholarly journals Medical Management of Asymptomatic Primary Hyperparathyroidism: Proceedings of the Third International Workshop

2009 ◽  
Vol 94 (2) ◽  
pp. 373-381 ◽  
Author(s):  
Aliya Khan ◽  
Andrew Grey ◽  
Dolores Shoback
Keyword(s):  
Hormone Replacement Therapy ◽  
Primary Hyperparathyroidism ◽  
Bone Turnover ◽  
Replacement Therapy ◽  
Serum Calcium ◽  
Medical Management ◽  
Task Force ◽  
International Workshop ◽  
Hormone Replacement ◽  
The Third

Abstract Background: Primary hyperparathyroidism (PHPT) is a common endocrine disorder that is frequently asymptomatic. The 2002 International Workshop on Asymptomatic PHPT addressed medical management of asymptomatic PHPT and summarized the data on nonsurgical approaches to this disease. At the Third International Workshop on Asymptomatic PHPT held in May 2008, this subject was reviewed again in light of data that have since become available. We present the results of a literature review of advances in the medical management of PHPT. Methods: A series of questions was developed by the International Task Force on PHPT. A comprehensive literature search for relevant studies evaluating the management of PHPT with bisphosphonates, hormone replacement therapy, raloxifene, and calcimimetics was conducted. Existing guidelines and recent unpublished data were also reviewed. All selected relevant articles were reviewed, and the questions developed by the International Task Force were addressed by the Consensus Panel. Results: Bisphosphonates and hormone replacement therapy are effective in decreasing bone turnover in patients with PHPT and improving bone mineral density (BMD). Fracture data are not available with either treatment. Raloxifene also lowers bone turnover in patients with PHPT. None of these agents, however, significantly lowers serum calcium or PTH levels. The calcimimetic cinacalcet reduces both serum calcium and PTH levels and raises serum phosphorus. Cinacalcet does not, however, reduce bone turnover or improve BMD. Conclusions: Bisphosphonates and hormone replacement therapy provide skeletal protection in patients with PHPT. Limited data are available regarding skeletal protection in patients with PHPT treated with raloxifene. Calcimimetics favorably alter serum calcium and PTH in PHPT but do not significantly affect either bone turnover or BMD. Medical management of asymptomatic PHPT is a promising option for those who are not candidates for parathyroidectomy.

scholarly journals Hormone-replacement therapy use, but not race, impacts the resting and exercise-induced GH response in postmenopausal women

2005 ◽  
Vol 153 (4) ◽  
pp. 527-533 ◽  
Author(s):  
J A Kanaley ◽  
I Giannopoulou ◽  
S Collier ◽  
R Ploutz-Snyder ◽  
R Carhart
Keyword(s):  
Hormone Replacement Therapy ◽  
Black Women ◽  
Replacement Therapy ◽  
Postmenopausal Women ◽  
Racial Differences ◽  
Hormone Replacement ◽  
Cycle Ergometer ◽  
Pulse Number ◽  
The Mean ◽  
Response To Exercise

Objective: This study examined the effect of hormone-replacement therapy (HRT) use on the incremental GH response to aerobic exercise in postmenopausal women and established whether racial differences in the GH response were seen at rest and in response to exercise. Methods: 13 white (n = 6, HRT; n = 7, no HRT) and seven black women (no HRT) were studied on two occasions, a control day and an exercise day (30 min at 70% VO2max on a cycle ergometer). Blood was sampled every 10 min for a 4-h period and analyzed for GH using an ultrasensitive chemiluminescent assay. Results: The mean 4-h GH concentration was higher on both study days in the HRT women than the non-HRT users. The integrated GH concentrations were greater in the HRT women both at rest and in response to exercise (rest, 352 ± 53 min μg l−1; exercise, 711 ± 57 min μg l−1; P < 0.01) than in the non-HRT women (rest, 157 ± 87 min μg l−1; exercise, 248 ± 94 min μg l−1). The incremental GH response was greater in the HRT users than in the non-HRT women (358 ± 130 versus 90.8 ± 94 min μg l−1, respectively; P < 0.05). GH-production rate during the 4-h period was greater in the HRT women than in the non-HRT women (P < 0.01), due to an increase in the GH mass secreted/pulse (P < 0.05), with no change in GH pulse number or GH half-life. No racial differences in the mean 4-h GH concentrations or integrated GH concentrations were found at rest or in response to exercise. Conclusion: HRT use resulted in a greater incremental exercise response compared with non-HRT users, due to changes in the secretory pulse characteristics in the HRT users. This study also demonstrated that no racial differences exist at rest and in response to exercise in the morning hours.

Chronic hormone replacement therapy alters thermoregulatory and vasomotor function in postmenopausal women

1997 ◽  
Vol 83 (2) ◽  
pp. 477-484 ◽  
Author(s):  
E. M. Brooks ◽  
A. L. Morgan ◽  
J. M. Pierzga ◽  
S. L. Wladkowski ◽  
J. T. O’Gorman ◽  
...  
Keyword(s):  
Hormone Replacement Therapy ◽  
Replacement Therapy ◽  
Postmenopausal Women ◽  
Hormone Replacement ◽  
Venous Occlusion ◽  
Cycle Ergometer ◽  
Vascular Conductance ◽  
Mean Body Temperature ◽  
Doppler Flowmetry ◽  
Vasomotor Function

Brooks, E. M., A. L. Morgan, J. M. Pierzga, S. L. Wladkowski, J. T. O’Gorman, J. A. Derr, and W. L. Kenney. Chronic hormone replacement therapy alters thermoregulatory and vasomotor function in postmenopausal women. J. Appl. Physiol. 83(2): 477–484, 1997.—This investigation examined effects of chronic (≥2 yr) hormone replacement therapy (HRT), both estrogen replacement therapy (ERT) and estrogen plus progesterone therapy (E+P), on core temperature and skin blood flow responses of postmenopausal women. Twenty-five postmenopausal women [9 not on HRT (NO), 8 on ERT, 8 on E+P] exercised on a cycle ergometer for 1 h at an ambient temperature of 36°C. Cutaneous vascular conductance (CVC) was monitored by laser-Doppler flowmetry, and forearm vascular conductance (FVC) was measured by using venous occlusion plethysmography. Iontophoresis of bretylium tosylate was performed before exercise to block local vasoconstrictor (VC) activity at one skin site on the forearm. Rectal temperature (Tre) was ∼0.5°C lower for the ERT group ( P < 0.01) compared with E+P and NO groups at rest and throughout exercise. FVC: mean body temperature (Tb) and CVC: Tb curves were shifted ∼0.5°C leftward for the ERT group ( P < 0.0001). Baseline CVC was significantly higher in the ERT group ( P < 0.05), but there was no interaction between bretylium treatment and groups once exercise was initiated. These results suggest that 1) chronic ERT likely acts centrally to decrease Tre, 2) ERT lowers the Tre at which heat-loss effector mechanisms are initiated, primarily by actions on active cutaneous vasodilation, and 3) addition of exogenous progestins in HRT effectively blocks these effects.

Short-term aerobic training and circulatory function in women: age and hormone-replacement therapy

2003 ◽  
Vol 104 (3) ◽  
pp. 267 ◽  
Author(s):  
Sonia KATYAL ◽  
Michael FREEMAN ◽  
Judith A. MILLER ◽  
Scott G. THOMAS
Keyword(s):  
Hormone Replacement Therapy ◽  
Replacement Therapy ◽  
Aerobic Training ◽  
Hormone Replacement ◽  
Short Term ◽  
Circulatory Function

Short-term aerobic training and circulatory function in women: age and hormone-replacement therapy

2003 ◽  
Vol 104 (3) ◽  
pp. 267-273 ◽  
Author(s):  
Sonia KATYAL ◽  
Michael FREEMAN ◽  
Judith A. MILLER ◽  
Scott G. THOMAS
Keyword(s):  
Hormone Replacement Therapy ◽  
Cardiac Function ◽  
Replacement Therapy ◽  
Plasma Volume ◽  
Aerobic Training ◽  
Hormone Replacement ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Short Term ◽  
Physiological Basis

The physiological basis of training responses in women, and particularly older women, is not well understood. Short-term aerobic training (STAT) was used to probe the effects of age and hormone-replacement therapy (HRT) on women's ability to rapidly change peak uptake (VO2max), plasma volume and cardiac function. A total of 39 females participated in the STAT programme: 15 younger (Y; aged 19–29 years), 12 postmenopausal women undergoing HRT and 12 non-medicating postmenopausal (PM) women (aged 60–75 years). Training consisted of ten sessions of cycling over a 2-week period, which progressed in duration from 20 to 60min and in intensity from 60–75% of maximum heart rate. Plasma volume (PV; as determined by Evan's Blue dye dilution), VO2max (cycle ergometry) and cardiac function (radionuclide ventriculography) were analysed using analysis of covariance or repeated measures ANOVA. All groups demonstrated similar increase in VO2max (Y, 13%; PM, 17%; HRT, 13%), but without a significant change in left-ventricular ejection fraction and diastolic function or volumes during supine exercise. PV expansion was observed among the Y group (7%; P<0.05) but not the PM group (2%; P>0.05) or women undergoing HRT (1%; P>0.05). Age and hormone-replacement status did not affect the magnitude of VO2max change. This study suggests that STAT improves VO2max, independent of central adaptations.

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