Cardiorespiratory fitness and health-related quality of life in women at risk for gestational diabetes

This study examined the associations of cardiorespiratory fitness (CRF) and leisure-time physical activity (LTPA) with health-related quality of life (HRQoL) in women at risk for gestational diabetes mellitus (GDM). The participants were 39 women planning pregnancy with a history of GDM and/or BMI >29 kg/m² . We assessed CRF by measuring maximal oxygen consumption (VO_2max ) during incremental cycle ergometer exercise until voluntary fatigue. LTPA was self-reported, and HRQoL assessed with the SF-36 Health Survey (SF-36). The mean (SD) VO_2max was 27 (6) mL·kg^-1 ·min^-1 , and the mean LTPA was 2.6 (1.7) h/wk. After controlling for BMI, VO_2max was positively associated with the SF-36 General Health scale (β 1.27, 95% CI: 0.09, 2.44, P=.035) and the Physical Component Summary (β 0.48, 95% CI: 0.14, 0.82, P=.007). The General Health scale (P=.023) and the Physical Component Summary (P=.011) differed even between those with very poor and poor CRF. After controlling for BMI, LTPA was positively associated with the SF-36 Physical Functioning scale (r_s =.34, P=.039), the General Health scale (β 3.74, 95% CI: 0.64, 6.84, P=.020), and the Physical Component Summary (β 1.13 95% CI: 0.19, 2.06, P=.020). To conclude, CRF and LTPA were positively associated with perceived general health and physical well-being in women planning pregnancy and at risk for GDM. Even a slightly better CRF would be beneficial for well-being among women with low levels of CRF.

Influence of weight reduction on muscle performance and bone mass, structure and metabolism in obese premenopausal women

Muscle performance, body composition and bone mass at the lumbar spine and proximal femur with DXA, structural traits at the tibia and radius with pQCT, and biomarkers of bone metabolism were assessed at baseline and after a three-month weight reduction in obese premenopausal women. Associations between changes in weight loss and bone traits were analyzed by linear regression analysis. The mean (SD) weight loss was 4.3 (4.5) kg ranging from 14.8 kg loss to 2.1 kg gain. Muscle performance was well maintained, while no signs of bone loss or structural deterioration were observed. Changes in bone resorption were significantly associated with weight change (for CTX, r=-0.34; p=0.043, and for TRACP5b, r=-0.35; p=0.032). There were borderline (p<0.1) negative correlations between changes in biomarkers and bone traits. Reduced fat mass was associated with slight mean increase in cortical density of the radial shaft. Also total body BMC increased slightly. Changes in both fat and lean mass were associated with a change in BMC. Our findings suggest that mild-to-moderate weight reduction modulated bone turnover slightly, but they do not support the common notion that such a weight reduction would compromise bone rigidity, possibly partly due to well maintained muscle performance.

Sleep-related disturbances and physical inactivity are independently associated with obesity in adults

OBJECTIVE

To study relationships between obesity, physical inactivity and sleep-related disturbances (obstructive sleep apnea (OSA), sleep duration, sleep disturbances concomitant with daytime tiredness) in adults (> or =30 years).

DESIGN

Cross-sectional study with a random population sample.

PARTICIPANTS

A total of 3377 men (mean age 52.3, s.d. 14.8, years) and 4264 women (56.4, s.d. 17.2, years).

MAIN OUTCOME MEASURES

Dependent variables, measured: Waist circumference (WC) and body mass index (BMI). Independent variables, from a detailed interview/questionnaire: probable OSA, other sleep-related disturbances, sleep duration, type and frequency of leisure physical activity. Age, mental health, smoking and education were included in analyses as potential confounders.

RESULTS

In men, OSA and physical inactivity increased likelihood for abdominal obesity (WC > or =102 cm). Physical inactivity also increased, but long (> or =9 h/day) sleep decreased likelihood for abdominal overweight (WC: 94-101 cm) in men. In women, abdominal obesity (WC > or =88 cm) was associated positively with OSA, moderate sleep-related disturbances, and physical inactivity. Education modulated the influence of age on abdominal obesity in both genders. Using BMI as the dependent variable did not change the general information obtained by the model. In addition, abdominal obesity was found to be an independent risk factor also in multivariable models predicting categories of a combined sleep duration and sleep disturbances.

CONCLUSIONS

Sleep duration and sleep-related disturbances are associated with obesity, even after controlling for OSA and physical inactivity. The results support the hypothesis of vicious circle between sleep and obesity.

Pulse wave velocity reference values in healthy adults aged 26?75�years

The stiffening of arteries is associated with various cardiovascular diseases. Arterial stiffening can be studied utilizing arterial pulse wave velocity (PWV), but the absence of reliable reference values for PWV has limited its use in clinical practice. The aim of this study was to establish a range of reference values for PWV. PWV was examined by measuring the time difference of systolic pulse waves in arteries from the aortic arch to the popliteal artery using whole-body impedance cardiography (ICG). The study population consisted of 799 individuals (age range 25-76 years), 283 of whom had no evidence of cardiovascular disease, and a low burden of risk factors was selected to represent an apparently healthy population. In healthy study population, PWV was higher in males (8 x 9 +/- 1 x 8 m s(-1)) than females (8 x 1 +/- 2 x 0 m s(-1), P<0 x 001). Young males had lower PWV values than old males. Correspondingly, young females also had lower PWV values than old females. PWV was clearly associated with age, and PWV was higher in young and middle-aged males than in females. There was no statistically significant difference between old males and females in PWV. In conclusion, whole-body ICG provides a practical method for PWV measurement. Reference values can be useful in the clinical management of patients, especially in detecting early vascular disease or an increased risk of cardiovascular complications.

Self-guided brisk walking training with or without poles: a randomized-controlled trial in middle-aged women

Walking with poles (Nordic walking, NW) has become popular. We compared training responses of brisk walking (W) or NW on cardiorespiratory and neuromuscular fitness. We randomized 121 non-obese sedentary women (aged 50-60) to an NW or W group (NWG, WG), to train 40 min four times weekly for 13 weeks. Intensity was based on subjective perception of exertion. Cardiorespiratory performance was assessed in four levels corresponding to 50%, 65%, 80% and 100% of peak VO(2). Fifty-four NWG and 53 WG subjects completed the study. The mean intensity was about 50% of heart rate (HR) reserve. The baseline peak VO(2) was 25.8 (SD 3.9) mL/min/kg. Both groups improved peak VO(2) similarly (NWG 2.5 mL/min/kg, 95% confidence interval (CI) 1.9-3.3; WG 2.6, CI 1.9-3.3). In the submaximal stages while walking with or without poles, HR and lactate decreased after training in both groups, but the changes were not statistically significantly different between the groups. Of the neuromuscular tests after training, the only significant difference between the groups was in the leg strength in the one-leg squat, favoring WG. In conclusion, both training modes improved similarly health-enhancing physical fitness, and they were feasible and safe.

Successful weight maintenance preserves lower levels of oxidized LDL achieved by weight reduction in obese men

OBJECTIVE

We studied the association between weight maintenance, oxidized low-density lipoprotein (ox-LDL) and other lipoproteins in obese men.

METHODS

A 2-month weight reduction phase (WRP) with a very-low-energy diet was followed by a 6-month weight maintenance period and an unsupervised 2-year follow-up. Ninety men entered and 68 (76%) completed the study. Subjects were analyzed as one group and after division into two subgroups: 20 most successful men in maintaining the lost weight (subgroup 1) and the remaining (n=48) men (subgroup 2). Ox-LDL was measured by quantifying the amount of conjugated dienes in LDL particles.

RESULTS

The mean (+/-s.d.) weight reduction at the end of the WRP (n=68) was 14% (confidence interval (CI) 12.9-14.7%, 14.5+/-4.2 kg, P<0.001). Ox-LDL decreased by 22% (CI 16.9-28.1, 12.3+/-15.4 micromol/l, P<0.001). At the end of the 2-year follow-up, the regain in weight from the end of the WRP was 11% (CI 9.0-12.4, 9.6+/-6.2 kg, P<0.001). The regain in ox-LDL was 30% (CI 18.7-41.2, 8.2+/-15.4 micromol/l, P<0.001). In subgroup 1 vs 2, the respective regains were 3% (CI 0.9-4.2, 2.2+/-3.0 kg, P=0.006) vs 14% (CI 12.7-15.6, 12.9+/-4.0 kg, P<0.001) regarding weight and 9% (2.0+/-6.9 micromol/l, P=NS) vs 39% (CI 23.7-53.9, 11.2+/-17.2 micromol/l, P</=0.001) in ox-LDL.

CONCLUSION

The favorable changes seen in ox-LDL particles and serum lipids during weight reduction could be maintained by keeping the weight reduced, which may indicate decreased risk of atherosclerosis. But weight regain causes a resurge of ox-LDL.

Food selection and eating behaviour during weight maintenance intervention and 2-y follow-up in obese men

OBJECTIVE

The aim was to assess long-term changes in food consumption and eating behaviour during and 2 y after dietary counselling in weight-reduced obese men.

DESIGN

Observational study from a randomised controlled trial.

SETTING

Outpatient clinic of a research institute.

SUBJECTS

A total of 36 subjects with complete data on food intake during the study. Subjects were obese (mean body mass index (BMI) 32.8 kg/m2) men aged 35-50 y, recruited by media advertising.

INTERVENTIONS

Dietary counselling was included in 2 months weight reduction with very-low-energy-diet and in 6 months weight maintenance programme, which also included physical activity counselling. This was followed by a 23 months unsupervised follow-up with yearly assessments. Food intake was assessed six times during the study by 4-day food records. Eating behaviour was assessed by Three-Factor Eating Questionnaire (TFEQ).

RESULTS

Increased consumption of low-fat cheese, low-fat margarine, vegetables and high-fibre bread, and decreased consumption of sugar, sausage, high-fat cheese, high-fat margarine, fat products and sweets were observed during dietary counselling. Most of these changes returned later to prestudy consumption level. The relapse in dietary changes was partly associated with scoring low in restraint and high in disinhibition and hunger.

CONCLUSION

In obese men, long-term maintenance of dietary changes was difficult. New ways to ease self-monitoring and increase self-efficacy might be necessary to improve maintenance of dietary changes.

Walking trials in postmenopausal women: effect of low doses of exercise and exercise fractionization on coronary risk factors

We studied the fractionization of walking training and searched for the minimum dose to affect coronary risk factors in two randomized controlled trials. Altogether 134 (Study I) and 121 (Study II) healthy, sedentary postmenopausal women started the trials, and 130 (Study I) and 116 (Study II) completed them. In Study I the exercise intensity was 65% of the maximal aerobic power (VO2max) and a total of 300 kcal was expended in one (Group W1) or two (Group W2) daily walking bouts. In Study II the exercise was continuous, and the exercise intensity (% of VO2max) and energy expenditure (kcal session(-1)) were 55% and 300 kcal (Group W3), 45% and 300 kcal (Group W4), 55% and 200 kcal (Group W5) and 45% and 200 kcal (Group W6). All the subjects walked 5 days a week. The outcome measures were blood pressure, serum lipoproteins and blood glucose and plasma insulin in fasting state and also during 2-h oral glucose tolerance test in Study I. There was no change in diastolic pressure in the original study groups, but in the combined exercise group (W1+W2) in Study I, the mean diastolic pressure declined by -3.0 mmHg (95% con-fidence interval (CI) -5.5 to -0.4) (P=0.025) in comparison with that of the controls. The mean blood glucose declined by -0.21 mmol L(-1) (CI -0.33 to -0.09) in Group W1 and -0.13 mmol L(-1) (CI -0.25 to -0.01) in Group W2 compared to controls (P=0.03). Also the 2-h glucose concentration decreased in Groups W1 and W2 compared to controls. Systolic blood pressure, serum lipoproteins and insulin levels did not change in Study I or Study II. We conclude that our training program with the greatest exercise dose, exercise intensity 65% of VO2max and weekly expenditure of 1500 kcal had a minimal, positive effect on diastolic pressure and blood glucose, and the effect was similar in one or two daily exercise session groups. This exercise dose is probably close to the minimum to affect coronary risk factors in healthy postmenopausal women. To get a more pronounced and clinically relevant effect, a greater exercise dose is needed.

Effects of walking or resistance training on weight loss maintenance in obese, middle-aged men: a randomized trial

OBJECTIVE

To investigate whether walking or resistance training improves weight maintenance after weight loss when added to dietary counselling.

DESIGN

Two months' weight reduction with very-low-energy-diet (VLED) followed by randomization into three groups (control, walking, resistance training) for 6 months' weight maintenance (WM) program and 23 months' unsupervised follow-up. During VLED and WM all groups received similar dietary counselling.

SUBJECTS

The main inclusion criteria were BMI >30 kg/m(2), waist>100 cm and physical inactivity (exercise < or = once a week). Ninety healthy, obese (mean BMI 32.9 kg/m(2) and waist 112.5 cm), 35-50 y-old men started the study and 68 were measured at the end of the study.

MEASUREMENTS

Weight and body composition assessed by underwater weighing. Exercise diaries and dietary records to assess energy balance.

RESULTS

During VLED the mean body weight decreased from 106.0 (s.d. 9.9) kg to 91.7 (9.4) kg. Weight was regained mostly during follow-up and in the end of the study the mean weight in groups was 99.9-102.0 kg. Exercise training did not improve short or long-term weight maintenance when compared to the control group. However, resistance training attenuated the regain of body fat mass during WM (P=0.0l), but not during follow-up. In the combined groups the estimated total energy expenditure (EE) of reported physical activity was associated with less weight regain during WM. EE of 10.1 MJ/week was associated with maintaining weight after weight loss. EE of physical activity tended to decrease after WM in exercise groups due to poor long-term adherence to prescribed exercise. Energy intake seemed to increase during follow-up.

CONCLUSION

Exercise training of moderate dose did not seem to improve long-term weight maintenance because of poor adherence to prescribed exercise.

The validity of predicted body fat percentage from body mass index and from impedance in samples of five European populations

OBJECTIVES

To test and compare the validity of a body mass index (BMI)-based prediction equation and an impedance-based prediction equation for body fat percentage among various European population groups.

DESIGN

Cross-sectional observational study.

SETTINGS

The study was performed in five different European centres: Maastricht and Wageningen (The Netherlands), Milan and Rome (Italy) and Tampere (Finland), where body composition studies are routinely performed.

SUBJECTS

A total of 234 females and 182 males, aged 18-70 y, BMI 17.0-41.9 kg/m(2).

METHODS

The reference method for body fat percentage (BF%(REF)) was either dual-energy X-ray absorptiometry (DXA) or densitometry (underwater weighing). Body fat percentage (BF%) was also predicted from BMI, age and sex (BF%(BMI)) or with a hand-held impedance analyser that uses in addition to arm impedance weight, height, age and sex as predictors (BF%(IMP)).

RESULTS

The overall mean (+/-s.e.) bias (measured minus predicted) for BF%(BMI) was 0.2+/-0.3 (NS) and-0.7+/-0.3 (NS) in females and males, respectively. The bias of BF%(IMP) was 0.2+/-0.2 (NS) and 1.0+/-0.4 (P<0.01) for females and males, respectively. There were significant differences in biases among the centres. The biases were correlated with level of BF% and with age. After correction for differences in age and BF% between the centres the bias of BF%(BMI) was not significantly different from zero in each centre and was not different among the centres anymore. The bias of BF%(IMP) decreased after correction and was significant from zero and significant from the other centres only in males from Tampere. Generally, individual biases can be high, leading to a considerable misclassification of obesity. The individual misclassification was generally higher with the BMI-based prediction.

CONCLUSIONS

The prediction formulas give generally good estimates of BF% on a group level in the five population samples, except for the males from Tampere. More comparative studies should be conducted to get better insight in the generalisation of prediction methods and formulas. Individual results and classifications have to be interpreted with caution.

Reduced oxidized low-density lipoprotein after weight reduction in obese premenopausal women

BACKGROUND

Several studies support the hypothesis that oxidation of low-density lipoprotein (LDL) promotes atherogenesis. Obesity is one of the risk factors of atherosclerosis, but it is not known whether obesity is related to LDL oxidation.

OBJECTIVE AND DESIGN

We investigated the effect of weight reduction and subsequent weight maintenance program on LDL oxidation in 77 obese premenopausal women (BMI 29-46 kg/m(2)). Another group of seven obese women served as a control group. Oxidized LDL was measured as baseline concentration of conjugated dienes in LDL lipids (ox-LDL). The weight reduction was performed in 12 weeks, using a very-low-energy diet.

RESULTS

The mean weight loss was 13 kg (92 vs 79 kg). During weight reduction, the concentration of LDL cholesterol decreased by 11%, the concentration of ox-LDL decreased by 40%, and the ratio of ox-LDL to LDL by 33%. The concentration of LDL antioxidant capacity (LDL-TRAP) decreased by 8%, but the decrease was caused by the decrease in LDL. The concentration of LDL, ox-LDL or LDL-TRAP did not change in the control group. The weight reduction correlated with the decrease of ox-LDL. During the subsequent 9 month weight maintenance programme, the concentrations of serum LDL (10%), ox-LDL (11%), LDL-TRAP (29%), and the ratio of LDL-TRAP to LDL (21%) decreased.

CONCLUSION

This study strengthens the evidence that the risk of atherogenesis is influenced favourably by weight reduction in obese women. This risk reduction is associated with a reduced oxidation of LDL.

Does physical activity prevent weight gain--a systematic review

This paper is a systematic review of research data on associations between physical activity and weight gain, with or without prior weight reduction. The selected studies were restricted to Caucasian (white) adults. Most studies with data on physical activity collected at follow-up, found an inverse association between physical activity and long-term weight gain. This finding was present in studies both with and without prior weight reduction. Prospective studies with physical activity measured at baseline, and randomized weight reduction interventions, gave inconsistent results regarding the effects of increased physical activity on weight change. The weighted mean weight regain in randomized studies with or without exercise training was 0.28 and 0.33 kg/month, respectively. Based on observational studies, it seemed that an actual increase in energy expenditure of physical activity of approximately 6300-8400 kJ/week (1500-2000 kcal/week) is associated with improved weight maintenance. This is more than was prescribed in most randomized trials, and certainly more than the participants actually achieved. Adherence to a prescribed exercise programme remains a big challenge. Before new methods to improve exercise adherence are found, the role of prescribed physical activity in prevention of weight gain remains modest.

Effects of walking training on weight maintenance after a very-low-energy diet in premenopausal obese women: a randomized controlled trial

BACKGROUND

Maintenance of weight loss is a core problem in the treatment of obesity. Physical activity may improve maintenance and metabolic risk factors associated with obesity.

HYPOTHESES

(1) A walking training program of moderate intensity, started after weight reduction by a very-low-energy diet, improves maintenance of weight loss and obesity-related metabolic disorders; and (2) the effect of the training program is related to the prescribed amount of physical activity, ie, a higher amount (energy expenditure) leads to more favorable results.

METHODS

The participants were premenopausal women with a mean body mass index of 34.0 kg/m(2). Eighty-two participants were randomized to this study; 74 participated in the follow-up assessment. A 12-week weight reduction by mostly a very-low-energy diet was followed by a 40-week maintenance program randomized in 3 groups: a control group with no increase in habitual exercise and with counseling on diet and relapse prevention; a walk-1 group, with a walking program targeted to expend 4.2 MJ/wk and diet counseling; and a walk-2 group, with a walking program of 8. 4 MJ/wk and diet counseling. Random permuted blocks within strata were used, with weight loss (in 3 classes) as the stratifying factor. After the intervention, the subjects were followed up for 2 years.

MAIN OUTCOME MEASURES

Primary outcomes were body weight, fat mass, and waist circumference at the 2-year follow-up. Secondary outcomes were the levels of serum lipoproteins and lipids, plasma glucose, insulin, and blood pressure.

RESULTS

The mean weight loss after weight reduction was 13.1 kg. The main outcome variables remained stable during the maintenance program, but increased during the follow-up period. Compared with the end of weight reduction, weight regain at the 2-year follow-up was 3.5 kg less (95% confidence interval, 0.2-6.8) and waist circumference regain 3.8 cm less (95% confidence interval, 0.3-7.3) in the walk-1 group vs controls. The secondary outcomes showed a partial relapse during the maintenance program, and a further regain during the follow-up period.

CONCLUSIONS

Inclusion of a walking program of moderate training regimen into a weight maintenance program improved maintenance of losses in weight and waist circumference.

Eating control and physical activity as determinants of short-term weight maintenance after a very-low-calorie diet among obese women

OBJECTIVE

To test the hypothesis that eating control and physical activity help maintain weight and waist circumference after a very-low-calorie diet.

DESIGN

A 12 week weight reduction (WR) phase, followed by a 40 week weight maintenance (WM) phase. For the latter, the subjects were randomised into a no-exercise group and one of two groups with a walking program.

SUBJECTS

Eighty-five obese (body mass index 29-46, mean 34), clinically healthy, premenopausal women.

MEASUREMENTS

Body weight, waist circumference, body composition, the measuring restrained eating, disinhibition and hunger, measured by Three Factor Eating Questionnaire (TFEQ), binge eating measured by the Bulimic Investigatory Test of Edinburgh (BITE), and number of daily steps measured by a pedometer.

RESULTS

The change (delta) in weight during WM was predicted by the following regression: deltaweight (kg)=5.23+0.45 deltaweight during WR+0.66 disinhibition during WM0.00039 daily steps during WM, r2=0.46, SEE 3.3 kg. The change in waist circumference during WM was predicted as deltawaist (cm)=0.76+0.75 deltaweight during WM0.00021 daily steps during WM, r2=0.67, SEE 2.6 cm. Exercise group assignment did not affect the changes in weight, waist circumference, or indicators of eating control during the maintenance program.

CONCLUSIONS

Control of overeating, as indicated by a lower disinhibition factor of the TFEQ, and daily physical activity, as indicated by a higher number of daily steps, were positive and independent predictors of weight maintenance after a very-low-calorie diet. The number of daily steps showed an independent association with change in waist circumference during weight maintenance, even after adjustment for weight change.

Additive effects of the mutations in the beta3-adrenergic receptor and uncoupling protein-1 genes on weight loss and weight maintenance in Finnish women

This study examined whether the Trp64Arg mutation in the beta3-adrenergic receptor (beta3AR) and the A-->G mutation in the uncoupling protein-1 (UCP-1) genes have associations with weight loss and subsequent weight maintenance. Seventy-seven obese (body mass index range, 29-46 kg/m2), clinically healthy, premenopausal women were studied. A 12-wk weight reduction by very low calorie diet (VLCD) was followed by a 40-wk weight maintenance phase. The subjects were divided into four groups according to their beta3AR and UCP-1 genotype: no mutation (control; n=37), only Trp64Arg mutation in the beta3AR gene (n=12), only A-->G mutation in the UCP-1 gene (n=23), and both mutations (n=5). Subjects with both mutations had a lower weight reduction during VLCD than the controls [-10.5+/-0.6 (+/-SEM) vs. -14.0+/-0.5 kg; P=0.051, by ANOVA]. During the maintenance phase, weight in subjects with both mutations increased by 5.8+/-1.5 kg, but remained unchanged in the controls (-0.5+/-0.8 kg; P=0.041). The changes in weight in subjects with only one of the mutation were close to the results in the controls. Resting energy expenditure, adjusted for fat mass, fat-free mass, and maximal aerobic power, did not change differently between the groups throughout the study. The results suggest that a combination of the Trp64Arg mutation in the beta3AR and the A-->G mutation in the UCP-1 genes may be associated with faster weight gain after a VLCD.

Effects of walking training on health-related fitness in healthy middle-aged adults--a randomized controlled study

The effects of walking training on VO2max, serum lipoproteins and plasma fibrinogen were studied in 119 healthy middle-aged persons. Training prescription was 65-75% of VO2max, 50 min/session, four times a week for 15 weeks. The net difference (between pre-posttraining changes in the walking and control group) was statistically significant for VO2max (0.14 l .min-1, 95% CI 0.04, 0.23), total cholesterol (-0.20 mmol.l-1, CI -0.34, -0.06), LDL cholesterol (-0.17 mmol.l-1, CI -0.29, -0.05), ratio of HDL cholesterol to total cholesterol (0.014, CI 0.005, 0.023), and triglycerides (-0.15 mmol.l-1, CI -0.26, -0.04). No statistically significant changes occurred in fibrinogen. The findings indicate that walking training of moderate intensity resulted in a modest increase in VO2max and minor but consistently favorable changes in serum lipoproteins.

Cardiovascular effects of Atenolol, scopolamine and their combination on healthy men in Finnish sauna baths

Indicators of cardiovascular strain were studied in 12 healthy young men under the influence of drugs affecting the autonomic nervous system during the course of taking a sauna bath. There were four bath sessions: one without a drug (control) and three with drug pretreatment (Atenolol 50 mg or Scopolamine 0.3 mg or their combination taken orally 2 h before the bath). The time spent in the hot room depended on the subjective rating of heat stress. Its mean duration at a temperature of 88 degrees C (dry bulb) was 22 (range 14-33) min and did not differ significantly among the sessions. In the Atenolol experiment the mean resting heart rate before the bath was significantly lower (P < 0.001, ANOVA of repeated measures) than in the other experiments. The increase in heart rate per minute of heat exposure was significantly lower (P < 0.001) in the Atenolol experiment and higher (P = 0.017) in the Scopolamine experiment than in the other experiments. The systolic blood pressure increased more slowly (P = 0.004) and the diastolic pressure decreased less (P = 0.02) in the Atenolol experiment than in the other experiments. Heart rate and blood pressure returned to their initial levels during the 30-min recovery after the heat exposure. The plasma noradrenaline concentrations increased approximately twofold during all of the bath sessions, whereas the plasma adrenaline and serum thromboxane B2 concentrations showed no consistent alterations. A small oral dose of Scopolamine alone or in combination with Atenolol produced no marked cardiovascular strain in healthy men during a sauna bath.

Haemodynamic and hormonal responses to heat exposure in a Finnish sauna bath

Eight healthy young men were studied during three periods of heat exposure in a Finnish sauna bath: at 80 degrees C dry bulb (80 D) and 100 degrees C dry bulb (100 D) temperatures until subjective discomfort, and in 80 degrees C dry heat, becoming humid (80 DH) until subjective exhaustion. Oral temperature increased 1.1 degrees C at 80 D, 1.9 degrees C at 100 D and 3.2 degrees C at 80 DH. Heart rate increased about 60% at 80 D, 90% at 100 D and 130% at 80 DH. Plasma noradrenaline increased about 100% at 80 D, 160% at 100 D and 310% at 80 DH. Adrenaline did not change. Plasma prolactin increased 2-fold at 80 D, 7-fold at 100 D and 10-fold at 80 DH. Blood concentrations of the beta-endorphin immunoreactivity at 100 D, adrenocorticotropic hormone (ACTH) at 100 D and 80 DH, growth hormone at 100 D and testosterone at 80 DH also increased, but cortisol at 80 D and 100 D decreased. The plasma prostaglandin E2 and serum thromboxane B2 levels did not change. Patterns related to heat exposure were observed for heart rate, plasma noradrenaline, ACTH and prolactin in the three study periods.

Cardiorespiratory strain of middle-aged men in mass events of long-distance cycling, rowing, jogging, and skiing

The heart rate of 11 39- to 53-year-old regularly exercising but nonathletic men was recorded during mass events of 132-km cycling, 35-km rowing, 33-km running, and 90-km cross-country skiing during 1 year. These measurements were related to the cardiorespiratory response in respective maximal exercise tests to determine and compare the strain of the four events. The mean event time of the subjects was 4 h 58 (+/- 34) min for cycling, 4 h 20 (+/- 35) min for rowing, 3 h 30 (+/- 29) min for running, and 8 h 29 (+/- 49) min for skiing. The respective mean heart rates were 153 (+/- 10), 137 (+/- 15), 159 (+/- 8), and 145 (+/- 5) bts/min, which represented 79.3 (+/- 6), 72.9 (+/- 13), 85.7 (+/- 4), and 72.8 (+/- 7) %VO2 max as determined from the event-specific HR/VO2 regression line. The proportion of event heart rates above the level representing the 90% event-specific maximal heart rate was 31.2% (+/- 19%) in cycling, 17.9% (+/- 26%) for rowing, 59.7% (+/- 24%) for running, and 21.6% (+/- 23%) for skiing. A statistical comparison of the mean event heart rates indicated that heart rate was lower in rowing than in jogging (P less than 0.01) and in cycling (P less than 0.05) and also lower in skiing (P less than 0.01) than in jogging. The present results showed that the cardiorespiratory strain of middle-aged nonathletic men during long-distance mass events of cycling, jogging, and skiing is high and relatively comparable to that of well-conditioned athletes.

Effects of mild physical exercise on serum lipoproteins and metabolites of arachidonic acid: a controlled randomised trial in middle aged men

To study the effects of physical exercise on biochemical risk factors for ischaemic heart disease 31 healthy middle aged men undertook regular physical exercise for two months and 29 served as controls in a randomised trial. In the men taking regular exercise serum cholesterol concentrations increased 26% more in the high density lipoprotein subfraction two (HDL2) and decreased 31% more in the subfraction three (HDL3) and 9% more in the low density lipoprotein fraction than in the control group. A tendency towards increased plasma 6-keto-prostaglandin F1 alpha concentration and decreased serum thromboxane B2 concentration was found during the period of regular exercise, but prostaglandin E2 concentrations remained unchanged. The increase in plasma 6-keto-prostaglandin F1 alpha concentration was associated with an increase in serum HDL2 cholesterol concentration in the group taking regular exercise. Our data suggest that mild regular physical exercise favourably influences cholesterol distribution in serum lipoproteins in healthy middle aged men and may have beneficial effects on circulating metabolites of arachidonic acid.