Decreased exercise blood pressure in older adults after exercise training: contributions of increased fitness and decreased fatness.

OBJECTIVE: To describe the contribution of changes in fitness and fatness resulting from exercise training on changes in submaximal exercise blood pressure (BP) during treadmill testing. DESIGN AND SETTING: Prospective, randomised, controlled trial. PARTICIPANTS: Sedentary older adults (n = 115) with untreated prehypertension or mild hypertension. INTERVENTION: Six-month supervised aerobic and strength training. MAIN OUTCOME MEASUREMENT: Systolic BP (SBP) was assessed at rest and during each stage of a maximal graded exercise test (GXT) that determined Vo(2)peak. General and regional fatness was assessed by anthropometry, dual-energy x-ray absorptiometry and MRI. BP changes were calculated for each GXT stage, and multivariate regression models were used to describe the association of changes in exercise BP with changes in fitness and fatness. RESULTS: After training, exercisers versus controls had significantly increased Vo(2)peak and significantly lower measures of general and regional fatness. Also, stage-specific SBP was significantly lower at stage 3 (-9.4 vs -1.6 mm Hg, p = 0.03) and stage 4 (-7.9 vs -1.2 mm Hg, p = 0.03). Pooled regression analysis across all stages showed that exercisers had a 7.1 mm Hg reduction in SBP, but this reduction fell short of statistical significance (p = 0.12) compared with controls. A 1.0 ml/kg/min increase in Vo(2)peak and a 1.0 cm decrease in waist circumference independently predicted a 1.0 mm Hg decrease in exercise SBP (p = 0.04 and p = 0.001, respectively). CONCLUSIONS: Decreased exercise SBP was independently associated with decreased waist circumference, a marker of abdominal obesity and increased fitness. These findings suggest that exercise training improves multiple factors that have an independent influence on SBP.

Exercise effects on cardiac size and left ventricular diastolic function: relationships to changes in fitness, fatness, blood pressure and insulin resistance.

OBJECTIVES: To determine exercise training effects on cardiac size and left ventricular (LV) diastolic function and relationships of exercise induced changes in physiological and body composition parameters with cardiac parameters. DESIGN: Prospective, randomised controlled trial. SUBJECTS: Men and women (63.6 (5.7) years, body mass index 29.5 (4.4) kg/m(2)) with untreated hypertension (systolic blood pressure (BP) 130-159 or diastolic BP 85-99 mm Hg). MAIN OUTCOME MEASURES: Cardiac size and LV diastolic function, peak oxygen uptake (Vo(2)), muscle strength, general and abdominal fatness, and insulin resistance. INTERVENTIONS: 6 months of exercise training versus usual care. RESULTS: When analysed by group at six months, cardiac size and LV diastolic function did not differ between exercisers (n = 51) and controls (n = 53), whereas exercisers had significantly higher peak Vo(2) (28 v 24 ml/kg/min) and strength (383 v 329 kg), and lower fatness (34% v 37%), diastolic BP (73 v 75 mm Hg) and insulin resistance (quantitative insulin sensitivity check index 0.35 v 0.34) versus controls (all p

Exercise blood pressure response is related to left ventricular mass.

An exaggerated SBP response to exercise has been associated with increased left ventricular (LV) mass in some but not all studies. A total of 43 women and 34 men, aged 55-75 years, without evidence of cardiovascular disease, with a mean resting BP of 142+/-9/77+/-8 mmHg had their BP measured at rest and during maximal treadmill exercise. LV mass was measured using magnetic resonance imaging. LV mass was adjusted for lean body mass, which was assessed by dual energy X-ray absorptiometry. LV mass was within the normal range for the majority of the subjects. Among the resting and exercise BP indices, maximal SBP was the strongest correlate of LV mass (r=0.41, P<0.05). In multivariate analysis, maximal SBP was independently associated with LV mass after adjustment for lean body mass and gender, explaining 3% of the variance (P<0.05). Maximal exercise SBP is a modest but still independent predictor of LV mass in older persons with normal LV mass. These results raise the possibility that the SBP response to maximal exercise is an early marker of LV hypertrophy.

Fitness, fatness and activity as predictors of bone mineral density in older persons.

OBJECTIVES: To determine relationships of bone mineral density (BMD) with fitness, physical activity, and body composition and fat distribution. DESIGN: Cross-sectional. SETTING: General Clinical Research Center, Johns Hopkins Bayview Medical Center, Baltimore, Maryland. SUBJECTS: Men (n = 38) and women (n = 46), aged 55-75 years with high normal blood pressure or mild hypertension but otherwise healthy. METHODS: Aerobic fitness (oxygen uptake) on a treadmill, muscle strength by one-repetition maximum, activity by questionnaire, abdominal obesity by magnetic resonance imaging; anthropometrics, and body composition by dual energy X-ray absorptiometry (DXA) which measured total fat and lean mass, and BMD for the total skeleton, lumbar spine (L1-L4) and total hip. RESULTS: Aerobic fitness did not correlate with BMD. Using multivariate analysis to ascertain independent contributions to the variance in BMD, in women, with adjustment for hormone replacement therapy (HRT), total skeleton BMD was independently related to muscle strength and abdominal total fat; total hip BMD to body weight; lumbar spine BMD to abdominal total fat. HRT also influenced BMD in the lumbar spine. In men, lumbar spine BMD was independently related to abdominal total fat physical activity and total hip BMD related to lower body strength. P < 0.05 for all of these correlations. CONCLUSIONS: Abdominal obesity and muscle strength emerge as predominant correlates of BMD in older persons with stronger relationships seen in women. Body weight and HRT also explained portions of the variance in BMD in women. Whether abdominal obesity is simply a marker for general obesity or has independent protective effects on bone is yet to be determined.