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Individuals in good health despite a sedentary lifestyle still benefit from initiating an exercise routine in middle age, according to a randomized study.

Changes in maximal oxygen uptake (VO₂max) indicated , increasing from 29.0 to 34.4 mL/kg/min) by the end of the intervention. In contrast, VO₂max stayed flat for controls (P<0.001 between groups), Benjamin Levine, MD, of Texas Health Presbyterian Hospital in Dallas, and colleagues found.

LV stiffness (measured as curve fit of the diastolic pressure-volume curve) fell from a constant of 0.072 to 0.051 (P=0.0018), whereas there was no change in the controls (0.0635 to 0.062, P=0.83), the authors reported online in Circulation.

Additionally, exercise increased LV end-diastolic volume, whereas pulmonary capillary wedge pressure was unchanged, meaning patients gained a greater stroke volume for any given filling pressure, Levine's group said.

"In previously sedentary healthy middle-aged adults, 2 years of exercise training improved maximal oxygen uptake and decreased cardiac stiffness. Regular exercise training may provide protection against the future risk of heart failure with a preserved ejection fraction by preventing the increase in cardiac stiffness attributable to sedentary aging," they concluded.

For their study, the investigators had randomized 61 middle-aged participants, 52 of whom stayed for 2 years in their exercise training (n=28) or attention control group (n=24). At baseline, participants exercised less than 30 minutes a day, three times a week.

Volunteers were excluded if they had hypertension, body mass index ≥30 kg/m², untreated hypo- or hyperthyroidism, obstructive sleep apnea, chronic obstructive pulmonary disease, tobacco use within the past 10 years, coronary artery disease, or structural heart disease.

The exercise training group had to work out at least 30 minutes for 4 to 5 days a week, each session unsupervised but tracked with heart rate monitors. In addition, exercise physiologists met participants monthly throughout the intervention as training frequency, duration, and intensity progressed over time.

Of note was the 88% adherence to exercise.

"This study also demonstrated that exercise training can be adhered to by middle-aged adults over a prolonged period, suggesting that this may be an effective strategy to mitigate the deleterious effects of sedentary aging on the heart and forestall the development of heart failure with a preserved ejection fraction," Levine and colleagues said.

The authors found no differences in results between men and women, but they cautioned that their study was not adequately powered to test for interaction by sex. Recruiting participants on a volunteer basis also may have limited generalizability to the general adult population.

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