How to Start Working Out Again

Resolving to get back into exercise or take up a new fitness routine is one of the best things you can do for your health.

But it can also be overwhelming. How do you motivate yourself to lace up your sneakers when you haven’t gone on a run for months? Should you jump back into the interval training program you tried before or search for something more fun? And how do you safely ramp up your workouts if you feel out of shape?

To help you start an exercise plan and stick with it, we tapped fitness pros for advice on setting realistic goals, reducing injury risk and actually enjoying yourself.

First, make it easy to win.

Trying to radically change your behavior for a broad goal like getting in shape requires a level of motivation that can be hard to sustain. Instead, set measurable, bite-size goals, such as getting at least 10 minutes of exercise daily.

It’s OK if you’re not matching what your peers are doing or even what you were able to achieve in the past. Pushing yourself too hard too fast will only make you more prone to exhaustion and injury, and may lead you to stop working out.

You are more likely to repeat an activity you enjoy, so try picking up a sport you liked in high school or bundle your workout with bingeing your favorite TV show or podcast. And cap how much you exercise — at least in the beginning — so that you can meet and even exceed your goal. This will encourage you to keep going.

“People get hyperfixated on cultivating motivation,” said Al Hyle, a strength coach who specializes in helping people with A.D.H.D., who sometimes struggle with starting activities. “You just need to do a little bit of something. Then the motivation is going to come after.”

Schedule time for muscle building.

Once you’re back into the swing of regular physical activity, start incorporating exercises to build muscle strength and flexibility. This will make it easier to do more strenuous activities and protect your joints from injury, said Dr. Gabrielle Lyon, a functional medicine practitioner based in New York and the author of “Forever Strong: A New, Science-Based Strategy for Aging Well.”

To start: Try body weight exercises like push-ups or squats at home or use weight machines at a gym. Most experts recommend doing three sets of eight to 12 reps for each exercise, focusing on your form. Then add one or two new exercises weekly until you’re working out all muscle groups — chest, back, shoulders, arms, abdominals and legs — at least twice a week.

Later on: Add resistance when you’re ready, or switch from a fixed number of reps to working out your muscles to exhaustion. You can determine when to start this by assessing your rate of perceived exertion. On a scale of 1 to 10, you should be just about in the middle, Mr. Hyle said. If it feels easier than that, make your workout more challenging.

Gradually increase cardiovascular endurance.

No matter what kind of exercise routine you get into, you’ll need to work on cardiovascular endurance. Most people can start with low-impact activities like walking or even just taking the stairs at the office.

To start: Strive to extend how long you can do light cardio by a few minutes every couple of weeks. Your heart’s ability to pump blood, also known as its stroke volume, improves fairly quickly, said Benjamin Gordon, an assistant professor of applied physiology and kinesiology at the University of Florida. “In just the first 10 days of training, we see about a 10 percent change in people’s stroke volume,” Dr. Gordon said. That means you’ll soon be able to work out for longer.

Later on: You want to build up to 150 minutes to 300 minutes of moderate-intensity aerobic activity every week to get the best benefits, Dr. Gordon said.

Plan backup workouts and celebrate achievements.

Prepare for the things that have tripped up your fitness routine in the past. For example, if you skipped exercising because you didn’t have time to fit it into your day, consider setting reminders to work out at 6 a.m., noon and 5 p.m. so you can make at least one of those times. Or try exercising in short bursts: Do squats or balance on one foot while brushing your teeth, or stash some hand weights at your desk to do a few reps while you’re on calls.

If your inner critic says you should stop because you’re never going to see results, practice saying something like “I’ve got this. I’m already stronger than I was when I started.”

Celebrate little steps toward fitness, Mr. Hyle said. Take pictures or do a monthly exercise assessment to measure your progress, or ask yourself whether it feels easier to carry your groceries. Just remember that it can take time to notice outward changes.

“What’s the rush?” Dr. Gordon said. “This is a lifestyle change, so you need to go in with the philosophy that you’re going to try and keep improving fitness for life.”