One woman runs through her local park an hour a day. Her male co-worker does 30 min of high intensity interval training 5 times a week. And his buddy lifts weights 4 days a week, twice per day designating each session for a specific set of body parts. Who is exercising the right amount? In other words.. who’s right?

First, let’s make one thing clear: one size never fits all. There has never been and will never be a single workout that is suitable for every person. Optimum workout activities, duration, intensity, frequency, and style are going to vary vastly from person to person based on your age, gender, personal fitness goals, injuries, overall health, background in fitness, work schedule, family obligations, interests, and good old genetics.

Right now you might be thinking: can I at least get a ballpark, here?

Well, according to a new analysis published in the journal Circulation, you should probably be exercising more than 30 minutes a day, at least.

Researchers reviewed 12 studies from the US and Europe involving 370,460 men and women with varying levels of physical activity. Over the course of 15 years, this group experienced 20,203 heart failure events. Each of the participants self-reported their daily activities along the way, allowing the team to keep track of their level of physical activity.

Current activity guidelines—set forth by the  American Heart Associationstipulate that for overall cardiovascular health, you need:

at least 30 minutes of moderate-intensity aerobic activity at least 5 days per week for a total of 150

OR

at least 25 minutes of vigorous aerobic activity at least 3 days per week for a total of 75 minutes; or a combination of moderate- and vigorous-intensity aerobic activity

AND

moderate- to high-intensity muscle-strengthening activity at least 2 days per week for additional health benefits.”

The bad news: researchers involved in this study found that those participants who followed these current guidelines only had “modest reductions” in heart failure risk compared to those who did not work out at all.

The good news: those who exercised twice and four times as much had “a substantial risk reduction” of 20 percent and 35 percent, respectively.

Researchers believe their findings show that physical activity and heart failure may be what is called “dose dependent,” meaning that the higher your level of physical activity, the lower your risk of heart failure. This finding held true across the age, gender, race, and geographic locations of the subgroups studied.

Senior author of the study and an associate professor at University of Texas Southwestern Medical School, Jarett D. Berry, believes that these findings should prompt physicians and health policymakers to strongly consider making new recommendations for greater amounts of physical activity to prevent heart failure.

Heart failure affects more than 5.1 million adults each year, resulting in health-care costs exceeding $30 billion annually.

One limitation to this study is it’s inability to compare the relationship of heart failure risk with different types of physical activity. It doesn’t look at running vs weight lifting vs rock climbing to determine which is better or worse for long term heart health.

That being said, whatever exercise you are doing needs to be for MORE than 30 minutes per day.

Still not sure where to start? Try creating a balance between the 4 different kinds of exercise: endurance, strength, balance, and flexibility.

Endurance exercise, also known as aerobic training, includes activities that increase your breathing and heart rate. This kind of activity is especially important and beneficial to the health of your heart, lungs, and circulatory system. Examples of endurance exercise includes walking/jogging, dancing, or yard work.

Strength exercise, also known as strength training or resistance training, focus on making your muscles stronger. This type of exercise is important for staying independent as you move into old age, so you can continue to carry out everyday activities, such as climbing stairs and carrying groceries. It’s also incredibly important for proper bone health and muscle mass and plays a key role in disease prevention. Examples of strength exercise includes lifting weights, using resistance bands, and body weight exercises.

Balance exercise is important because proper balance is not only going to allow you to complete more advanced moves of other exercise types (such as movements that involve standing on one leg, balancing on a slack rope, or tumbling), but it will also help prevent falls in older adults. Examples of balance exercise includes standing Tai Chi, certain yoga poses, and slacklining.

Flexibility exercise is important for maintaining or increasing your range of motion. Stretching is important if you want to complete advanced movements that require an impressive range of motion. It’s important for maintaining movement through old age. It’s also important for releasing tension in the body, and recovering from strenuous workouts. Examples of flexibility exercise includes touching your toes, deep lunges, and many yoga poses.

You need a combination of exercises for optimal health, and some forms of exercise overlap. You might have noticed that Yoga is great for flexibility and balance, but it’s also great for strength. Lifting weight is great for increasing strength, but when done at a certain level of exertion and speed can also double as an aerobic exercise.

When you’re thinking about starting a new workout regime the most important thing to figure out is what you enjoy doing. If you enjoy it, you’re much more likely to stick with it. And even the best exercise in the world isn’t going to anything for you if you can’t get yourself to stick to it.