Regular Exercise Boosts Effectiveness of 'Flu Shot

Source: Tufts University
October 11, 2002 (Reviewed: October 19, 2004)

Older adults are advised to get a yearly 'flu shot, yet their bodies' natural ability to withstand illness may not be optimal enough to make the vaccination fully effective. Because exercise can improve immune function, researchers set out to determine whether regular exercise would have an effect on older adults' immunity following 'flu vaccination. The results are published in the Journal of Gerontology.

The significance of the 'flu

Decreased immune function is common in older adults and may be part of the reason why many seniors are more susceptible to infectious disease. One such infectious disease - the 'flu - is one of the leading causes of death among seniors. And although many seniors get vaccinated, studies have shown that the effectiveness of the vaccine may be lower than it is in younger adults.

At the same time, it's been shown that certain lifestyle factors, such as diet, exercise, and stress management, may influence some measures of immunity. The researchers here wanted to see if such factors would influence older adults' immune response following the 'flu shot.

Comparing different activity levels

The researchers studied 56 adults aged 62 and older who did not have conditions that could otherwise affect their immunity (such as cancer or autoimmune diseases). They asked the participants about the intensity and the frequency of their physical activity during the previous year and then classified people into three groups: active, moderately active, and sedentary (inactive).

All of the study participants received 'flu shots during the same 2-week period and then had blood drawn 14 days later, to have specific components of their immune function measured.

The most active people had the greatest benefits

The blood tests showed that the people who were the most active had greater levels of certain antibodies (meaning greater immune response to the vaccination), compared with people who were only moderately active or inactive.

How might exercise influence immunity?

It is not known exactly how exercise may positively influence immunity, and, in this case, immune response specifically to the 'flu shot. Immune function is very complex, and many factors contribute to it. The authors of this study also point out that overall health status may affect immune response much more than exercise alone. Important differences between those who exercised and those who did not may not have been identified in this study, which focused solely on physical activity.

It's also important to note that this was an observational study, meaning that the researchers observed the exercise levels of free-living people and whether their exercise had any impact on their post-vaccination immunity. It was not a controlled clinical trial, in which subjects would be randomly assigned to a specific exercise category. Therefore, there is the potential for discrepancies between how much people actually exercised and how much exercise they reported.

But because the results of this study were promising, the researchers say they're planning a clinical trial to further test the hypothesis.

More reason to exercise

In the meantime, this study certainly adds to existing evidence that exercise can benefit your health in numerous ways as you age. It not only makes your muscles, bones, and heart strong, but it may also increase the power of your immune system.

Source

• Exercise and psychosocial factors modulate immunity to influenza vaccine in elderly individuals. ML. Kohut, MM. Cooper, MS. Nickolaus,  et al., J Gerontol, 2002, vol. 57, pp. 557--562

Related Links
Exercise May Boost Immunity
Lifting Weights May Boost Heart Health
It's Never Too Late To Get Moving
Moving for Mental Fitness
To quickly access additional accurate information on this and other nutrition-related topics, visit Tufts University's Nutrition Navigator

Please take a moment to give us your comments. For questions about Health matters you may check our "Questions & Answers" Portal and Service.