If you’re looking to improve your cardio fitness, immune system, metabolism, and mental health, regular walking checks all the boxes. And for those who like extra credit and want to increase the health benefits even more, you can take your walking speed up a few notches to the “brisk” level. Apparently, it could actually add years to your life: Recent research found that a lifetime of brisk walking can lead to DNA changes equivalent to a 16-year younger biological age by midlife. That’s one seriously impressive perk!

But how do you determine whether you’re walking briskly or just taking a normal stroll?

What is brisk walking?

What constitutes a brisk walk varies by a person’s baseline individual fitness level, so the best way to tell how hard you’re working is by using the Borg Perceived Exertion Scale, says Lauren Elson, MD, a board-certified sports medicine, and physical medicine and rehabilitation physician with Spaulding Rehabilitation in Massachusetts.

The Borg scale uses a self-determined rating between six and 20 to measure physical activity intensity based on sensations such as increased heart rate, breathing, and muscle fatigue—in other words, your “perceived exertion” level. A six rating is physical activity perceived as “no exertion” (think: lying flat on the floor) while a 20 rating is “maximum effort” (think: sprinting as fast as you possible can). A perceived exertion rate of 12 to 14 typically indicates you’re performing moderate-level activity—which is right where you want to be for a brisk walk.

“’Brisk walking’ would fit in the category of ‘moderate activity’—breathing heavily, [but] able to hold brief conversations, still somewhat comfortable, but becoming more challenging,” says Elson, who’s also an instructor at Harvard Medical School.

Whether you’re a young adult, a senior, or somewhere in between, the Borg scale is a good gauge to determine how hard you’re working because it’s based on how you feel and not a predetermined formula that may not apply to your fitness level, like hitting a particular pace.

Physical changes that come with age such as decreased muscle mass and aerobic capacity can lower your average walking speed. (Men also typically walk slightly faster than women, FWIW.) Research has found that walking speed decreases by about 0.00037 meters per second per year—meaning it will take the average 60-year-old about 1.2 minutes longer to walk 1 kilometer (.62 miles) than the average 20-year-old. Starting in our 60s, the decrease in average walking speed becomes more pronounced—going from a decrease of about one to two percent per decade before age 62 to about a 16 percent decrease per decade after age 62.

How to increase walking intensity and become a faster walker 

The Borg scale can also help you determine if you need to adjust your intensity level to put your walk into the “brisk” category. For example, the CDC recommends that if you’re aiming for moderate intensity but find your fatigue and breathing are “very light” (about a 9 on the scale), you should increase your effort to a level that feels “somewhat hard” (12 to 14) on the scale.

No matter your fitness level or age, there are ways you can increase your walk’s intensity and up the health benefits. “Age does affect speed and recovery time, but it is always possible to improve with an appropriate plan,” says Elson. Here are a few ways she suggests doing that.

Make sure to use proper form 

Think of walking like you would weightlifting, Pilates, or any other form of training—technique matters. Walk with your head high (look forward not down), and swing your arms back and forth naturally, advises Elson. Make sure to keep your back straight, your shoulders relaxed and down, and engage your core.

Try intervals

Interval training involves alternating faster-paced increments of walking with slower paced ones. High-intensity interval training, which can be done with walking, has been shown to reverse muscle aging at the cellular level. It will also ease you into walking faster more comfortably.

Elson recommends walking at an average pace for about five minutes, then walking briskly for 30 seconds, and repeating the pattern five to 10 times. Eventually, you can increase the amount of time you’re walking briskly.

Use gravity

Walking on any kind of upwards incline, whether on a hill outdoors or a treadmill, will increase the intensity and improve your lower-body strength so that you eventually can walk faster.

Skip the dumbbells

Though you’ve probably seen people walking with a light weight in each hand, doing so throws your natural gait off balance, affecting your form and possibly causing injury. “Strength should come from the core, so putting weights on the extremities is not great,” says Elson.

Work up to it gradually

If you have limitations or have never done a walking routine before, don’t just take off on a brisk walk right out of the gate. Start slowly, beginning your walks at a more leisurely pace, then increasing your speed after several minutes. Eventually you can work your way up to longer stretches—but the fact that you’re out there moving is already a positive, says Elson

“Any walking is better than none and multiple short walks may be equivalent to one long one. Just walking 30 minutes a day has been shown to have benefit,” she adds.

Set yourself up for success

Finally, before any walk Elson advises warming up for at least five minutes doing moves like leg swings, then cooling down and stretching afterwards. Also don’t forget to invest in a pair of comfortable walking shoes—it’s a small price to pay to reap the substantial ROI brisk walking can bring to your overall health.