You're not alone if you're confused about whether you're exercising enough. Many people are unsure whether they regularly hit an acceptable level.

Maybe you make time for a workout a few times a week. Is that often enough? Or maybe you do a little gardening or take your dog for a leisurely walk every day. Does either count as exercise?

Here's what JJ Rodriguez, a clinical exercise physiologist at Houston Methodist, has to say about how much is enough when it comes to exercise.

How many days a week should you exercise?

"To reap the full health benefits of exercise, you'll need to reach an optimal quantity of it — which is at least 150 minutes of moderate-intensity exercise per week for adults," says Rodriguez. "Split evenly throughout the week, this breaks down to about 30 minutes per day."

This is why many brands of fitness trackers set the standard daily exercise goal at 30 minutes.

For instance, you've gotten enough optimal exercise once you've closed your green ring or filled your lightening bolts. And, ideally, you do so every single day.

(Of course, you don't have to use a fitness tracker for your exercise to count.)

You can also spread your 150 minutes throughout the week however you like. Maybe for you that's three longer workouts per week instead of 30 minutes per day.

Still, all of this isn't to say you don't benefit from getting less than 30 minutes of exercise per day. You definitely do.

"If you don't close your rings or fill your bolts, it may feel like the exercise you did wasn't worth it, but that's not the case," adds Rodriguez. "Getting 150 minutes of moderate-intensity exercise a week is the gold standard as far as optimal health goes, but any exercise is better than none."

What counts as moderate-intensity exercise?

Not to make things even more confusing, but when it comes to getting "enough" exercise, we need to talk about intensity, too.

"When we are talking about the optimal exercise that comes with the most significant health benefits — meaning it's proven to reduce your all-cause mortality, improve your heart and lung health and provide metabolic benefit, including lowering your blood sugar and cholesterol — we're talking about exercise that's moderately intense," says Rodriguez. "What does that mean? It's the activities and workouts that elevate your heart rate and increase your breath for a prolonged period of time."

The exact heart-rate range a person needs to reach — and sustain — for it to count as moderate intensity varies based on fitness level and age. But, in general, try to maintain a comfortable pace that invokes deeper breathing but still allows for conversation.

This can be subtle, though, so you may find that letting your fitness tracker seamlessly monitor what counts as exercise in the background is easiest.

"The technology in fitness trackers is extremely helpful on the exercise tracking front," explains Rodriguez. "Each brand defines exercise slightly differently, but they're all essentially doing the same thing — monitoring your movement and giving you exercise credit for the time you spend doing things that elevate your heart rate."

Examples of moderate intensity exercise include:

• Taking a brisk walk
• Jogging or running
• Swimming
• Riding a bike
• Dancing
• Hiking
  
  

But it could also be spontaneous, such as walking up flights of stairs or sprinting to catch the bus.

What if my fitness tracker says I'm not getting enough exercise?

Wondering why you don't see some of the more popular exercises on the list above?

The explanation may also help you understand why your tracker only counted 20 minutes of exercise during your 60-minute yoga session.

"One tip I always recommend is to make sure you're initiating the exercise tracking feature on your device when you're active so it knows to count the minutes you're being intentional about your movement, regardless of what's happening with your heart rate," adds Rodriguez.

This is important since some types of exercise we know are beneficial to our health — yoga, Pilates, weightlifting — usually don't maintain moderate intensity.

"When we're sticking to the strict definition of optimal exercise, we're restricted to activities that are moderately intense from an oxygen consumption and heart rate standpoint," says Rodriguez. "So this is what fitness devices are looking for. The catch is that not all exercise gets your heart rate up consistently enough for it count as this. But if you let your device know you're working out, as long as you're moving, most are set up to give you credit."

This is why Rodriguez recommends an alternate way of thinking about exercise, as well as which activities count toward it.

Simplify how you approach "enough exercise" by thinking of it as getting enough quantified movement

The optimal exercise amount (150 minutes per week) and intensity (moderate) is considered to provide for the gold standard of health because it's proven to have numerous benefits.

But exercises that build strength in your core, legs, arms and shoulders provide health benefits, too — including improving your mental health and maintaining muscle tone, mobility and flexibility. These workouts don't always hold your heart rate at medium intensity, but they are just as important, maybe more.

So, here's Rodriguez's more simplified way of approaching things.

"Exercise is simply quantified movement," he says. "It's taking some form of physical activity, putting a value to it and sticking with it consistently."

The benefit is that this takes into account everything we know about exercise — from the heart health benefits of cardio to the functional benefits of strength training — and combines it into the overarching reason why we exercise in the first place: to stay healthy and active for longer.

"Whether it's your heart muscle, lung muscles or leg muscles, I always tell people that if you don't use it, you will lose it," Rodriguez adds. "So any quantifiable activity that gets you moving comes with tremendous benefit, regardless of what we label as optimal or what your tracker says."

Ideally, your quantified movement would be 150 weekly minutes of exercise that's moderately intense — for you, specifically — plus some strength training and mobility, like yoga or body weight exercises. But, again, any amount and intensity of purposeful movement is better than none.

"If you can get hooked on a few activities you enjoy doing and can get them done consistently, I'd rather you do that then get overwhelmed by whether what you're doing technically counts as exercise or not," says Rodriguez.