If it’s been a long time since you’ve exercised and you’re feeling less than fit, you might think that it’s too late to make a change. But you’re wrong. You can improve your fitness at any age.

“The stories in this area are actually very dramatic. Even people 100 years old or older can build muscle strength,” says Dr. Edward Phillips, assistant professor of physical medicine and rehabilitation at Harvard Medical School.

Dr. Jonathan Bean, a professor in the same department, describes the case of a 101-year-old man who wanted to be able to wheel his own wheelchair down the hall to read the newspaper. The man embarked on a weight training plan. “He got to the point where he could use a walker to go down and read the newspaper,” says Dr. Bean. This far surpassed his original goal. It’s an extreme illustration, but a potent one, of Dr. Bean’s point: it’s never too late.

That said, there are some limits to how much you can progress. “Workouts aren’t going to turn someone in their 80s, 90s or 100s into someone who is 40 or 50 years old, but most people can get stronger and improve their endurance,” says Dr. Bean.

Mental limitations

Today, only an estimated 40% of American adults get 150 minutes of moderate-intensity aerobic exercise a week, the low end of what the government recommends. And many people who do walk or get other aerobic exercise often don’t meet the second part of the government’s recommendation, twice-weekly strength training. Only 20% of adults meet that goal, says Dr. Phillips. “We’re sacrificing our healthy older years by not moving,” he says.

Often the barrier that keeps people from moving as much as they should is mental. “Some people assume, ‘Well, I’m 70, I can’t lift that, or I can’t go skiing or bike riding, because I’m too old.’ They can’t, not because they physically would be unable to, but because they’ve made the decision that they can’t mentally,” says Dr. Phillips. “Even among those of us who are into fitness, there may be an exaggerated sense of ‘I can’t do that because I’m older.'”

Test yourself: How strong are you?

One test of strength and power is a simple chair test. Sit in a chair with your arms crossed across your chest. Set a timer for 30 seconds and see how many times you can move from a sit to a stand, keeping your arms crossed. Use the table below to determine whether you need to improve.

“This chair exercise tests both strength and power. Strength is measured by whether you can get up off the chair, but power is measured by how quickly you can do it,” says Dr. Edward Phillips, assistant professor of physical medicine and rehabilitation at Harvard Medical School.

If you want to improve your score, use this same set of movements as an exercise to build strength:

1. Sit in a chair with your hands crossed on your chest or held out in front of you at chest level. Your feet should be flat on the floor, hip-width apart, and directly beneath your knees.

2. Lean forward slightly and slowly stand up. Hold.

3. Slowly sit down with control.

Do this 10 times for a set, and then rest for a minute or two. Try to build up to three sets.

To get the most from this exercise, press your heels into the floor and tighten your buttocks as you stand up to help you balance. Steady yourself before you sit down. Exhale as you stand, inhale as you sit.

Need an easier version of this exercise to get started? Place your hands on your thighs (or use a chair with armrests) to assist you as you stand up and sit down. Need more of a challenge? Modify the exercise by placing your right foot slightly in front of your left one, keeping both feet flat on the floor. Stand up and sit down. Do this 10 times, then repeat with the left leg in front.

Improving your health

If you want to get started on a fitness plan, check in with your doctor first before you start exercising. “Provided you don’t have any major contraindications, exercising is a great thing to do,” says Dr. Bean.

Typically, you should focus your efforts in three different areas:

  • cardiovascular fitness
  • strength
  • balance and flexibility.

If you are looking to improve your fitness, start gradually. Also set reasonable expectations, says Dr. Phillips.

“One of the things that we’ve done in our work is to look at what are the ingredients of exercise that help people to function better,” he says. Most people want to maintain their level of physical functioning. “Ultimately, they want to be able to function the best they can, and advance and not move backward,” he says.

To improve your physical performance, gradually increase the difficulty as you progress, no matter where you’re starting from. “The most important thing for people to recognize is that even exercising once a week makes a difference if they were not doing that before,” says Dr. Bean.

When performing an activity, be aware of how hard you are working, something called perceived exertion. “People should be working at a level that is somewhat hard when they are exercising,” says Dr. Bean. You’ll know that you are working at moderate intensity if you can talk during your workout, but not sing. Monitor and track your perceived exertion over time to see how you’re doing. For example, if you start out walking once a week, gradually increase the number of days, the amount of time you walk, or your speed as your walk gets easier and your perceived exertion drops.

To build strength, gradually add weight or resistance to your workouts. “Increase the weight by 10% every one to two weeks if you can,” says Dr. Bean.

If you are working on your flexibility, start by testing your current range of motion on all your joints. “Some people are born more flexible than others, so progress in this area is very individual,” says Dr. Bean.

Balance can be improved by using some simple strategies. “Something as simple as balancing on one foot can help your balance improve,” says Dr. Phillips. Practice standing on one foot a few times a week, and you can improve demonstrably. “That’s a really potent thing, and any little advantage that you get will reduce your risk of falling,” says Dr. Phillips.

Improving your balance and reflexes makes it more likely that you will be able to catch yourself if you lose your balance and avoid a fall to the ground.

Remember, if you don’t increase the difficulty of your exercise routine, your fitness level will stay the same. “Your body adapts to the degree to which you push it. But we also don’t want people to overdo it and create an injury,” says Dr. Bean.