Exercise which can achieve both cardiovascular function and muscle strength "would be a preferred mode of training for older persons", say investigators.
Experienced practitioners of Tai Chi, the traditional Chinese mind-body exercise now enjoyed worldwide, have been shown in a study of older subjects to have improved expansion and contraction of arteries according to cardiac pulsation (arterial compliance) and improved knee muscle strength.
The findings, say the investigators, of better muscle strength without jeopardising arterial compliance suggest that Tai Chi may well be a suitable exercise for older people to improve both cardiovascular function and body strength. A number of studies, they explain, have shown that strength training to improve muscle function and offset the effects of ageing have also been accompanied by a decline in arterial compliance. "Evidence that strength training could change arterial compliance in middle-aged and older subjects is still elusive," they note.
As background to their report, the investigators explain that arterial stiffness - when an artery fails to distend or rebound in response to pressure changes - is closely associated with cardiovascular diseases, possibly through elevated blood and pulse pressure and atherosclerosis. Arterial compliance, therefore, has been identified as an important predictor of cardiovascular health in the elderly and a therapeutic target for physical exercise in the prevention of cardiovascular disease.
The study, published online today in the European Journal of Preventive Cardiology, involved 65 elderly subjects from Hong Kong, 29 recruited from local Tai Chi clubs who had each practised Tai Chi for at least 1.5 hours a week for three years, and 36 controls with no Tai Chi experience. All subjects' physical activity levels were defined according to metabolic index units as light, moderate and heavy - but there were no differences between the two groups.
Initial results showed that the Tai Chi subjects were better in almost all haemodynamic observations - including blood pressure, vascular resistance, and pulse pressure. Measurements also showed that both large and small artery compliance was significantly higher in the Tai Chi group (by 40-44%). Additional analysis showed that the Tai Chi subjects had greater average muscle strength in both their knee extensors and flexors.