Today is Martin Luther King Jr. Day, a time to celebrate the birthday and reflect on the accomplishments and legacy of Mr. King. It is also a national day of service on which people are encouraged to use their day off from work or school to volunteer in their community. Individuals and groups across the country participate in community service, with some making this their first-time volunteer effort and many more continuing a year-round commitment to service.

You can maximize your impact in community service activities by being fit and healthy. To be sure, there are ways that people of all physical abilities can contribute, but many service opportunities require a baseline level of fitness to participate. And it is certainly more enjoyable to volunteer if you aren’t being pushed to your limits.

In fact, many service activities are similar in exertion to many forms of exercise and some may be consistent with maximal exercise. Unfortunately, the common pattern of inactivity and low fitness can limit people’s ability to function optimally at school, work, or in leisure-time activities, including community service.

We classify the intensity of activities in units called metabolic equivalents, or METs. One MET is the energy expended sitting at rest, so other activities would represent multiples of that. For example, walking at 2.5 mph is about 3 METs and running at 6 mph is almost 10 METs. The MET values for hundreds of exercise, occupational, household and leisure activities have been collected in the Compendium of Physical Activities.

Using this resource, the intensity of common community service activities can be determined.

For example, community clean-up efforts in parks and other public spaces often involve picking up trash, landscaping and cleaning facilities. These activities generally range in intensity from 3 to 6 METs and involve lifting, carrying and other whole-body movement, much like exercise. While people of all ages can participate in these activities, spending a full day does require a higher level of fitness.

Other programs that involve construction, like building a home for Habitat for Humanity, would have an even higher intensity. Construction in general is about 4 METs, but that can vary from light carpentry (2.5 METs) to carrying heavy tools and building materials (8+ METs). This is a similar intensity to circuit training at the gym or running outdoors.

Participating in events like community marches, walks or races to raise money or awareness about important issues also requires being fit. Walking is reasonable for most people but running requires more training and effort. Long marches or volunteering at other events can mean hours on your feet, too. No matter the event, you want to be fit enough that you can enjoy participating, rather than merely surviving the day.

The good news is that there is something everyone can do. For example, donation centers like the Salvation Army offer many ways to help. While the fitness requirements of receiving furniture and boxes of donated clothes — lifting and carrying heavy loads — are consistent with many forms of exercise, organizing items and folding clothes are lighter in intensity and appropriate for almost everyone who wants to volunteer.

The important thing is to participate in community service activities on MLK Day and throughout the year. Regular exercise can help you improve your strength and endurance to allow you to do more. You already know that exercise is good for your health, now you know that it is also good for the health of your community.