Keeping fit is an important thing you can do for your health. There are many physical activities you can do to stay fit. Understanding these fitness terms can help you make the most of your exercise routine.
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Activity Count
Physical activity is any body movement that works your muscles and requires more energy than resting. Walking, running, dancing, swimming, yoga, and gardening are a few examples of physical activity.
Source: 
National Heart, Lung, and Blood Institute
Aerobic Exercise
Aerobic exercise is activity that moves your large muscles, such as those in your arms and legs. It makes you breathe harder and your heart beat faster. Examples include running, swimming, walking, and biking. Over time, regular aerobic activity makes your heart and lungs stronger and able to work better.
Source:
National Heart, Lung, and Blood Institute
Basal Metabolic Rate
Basal metabolic rate is the measure of the energy necessary for maintaining basic functions, such as breathing, heart rate, and digestion.
Source:
NIH MedlinePlus
Body Mass Index
Body Mass Index (BMI) is an estimate of your body fat. It is calculated from your height and weight. It can tell you whether you are underweight, normal, overweight, or obese. It can help you gauge your risk for diseases that can occur with more body fat.
Source:
National Heart, Lung, and Blood Institute
Cool Down
Your physical activity session should end by gradually slowing down. You can also cool down by changing to a less vigorous activity, such as moving from jogging to walking. This process allows your body to relax gradually. A cool down can last 5 minutes or more.
Source:
National Heart, Lung, and Blood Institute
Energy Balance
The balance between calories you get from eating and drinking and those you use up through physical activity and body processes like breathing, digesting food, and, in children, growing.
Source:
National Institute of Diabetes and Digestive and Kidney Diseases
Energy Consumed
Energy is another word for calories. What you eat and drink is "energy in." What you burn through physical activity is "energy out."
Source:
National Heart, Lung, and Blood Institute
Flexibility (Training)
Flexibility training is exercise that stretches and lengthens your muscles. It can help improve your joint flexibility and keep your muscles limber. This can help prevent injuries. Some examples are yoga, tai chi, and pilates.
Source:
National Heart, Lung, and Blood Institute
Heart Rate
Heart rate, or pulse, is how many times your heart beats in a period of time — usually a minute. The usual pulse for an adult is 60 to 100 beats per minute after resting for at least 10 minutes.
Source:
National Heart, Lung, and Blood Institute
Maximum Heart Rate
The maximum heart rate is the fastest your heart can beat.
Source:
National Heart, Lung, and Blood Institute
Perspiration
Perspiration, or sweat, is a clear, salty liquid produced by glands in your skin. It is how your body cools itself. Sweating a lot is normal when it is hot or when you exercise, feel anxious, or have a fever. It can also happen during menopause.
Source:
NIH MedlinePlus
Strength Training
Strength training, or resistance training, is exercise that works your muscles by making you push or pull against something. It strengthens your muscles and can improve your bone strength and balance. Some examples are lifting weights, working with resistance bands, and doing push-ups and pull-ups.
Source:
National Institute of Diabetes and Digestive and Kidney Diseases
Target Heart Rate
Your target heart rate is a percentage of your maximum heart rate, which is the fastest your heart can beat. It is based on your age. The activity level that is best for your health uses 50–75 percent of your maximum heart rate. This range is your target heart rate zone.
Source:
National Heart, Lung, and Blood Institute
Warm Up
Your physical activity session should start at a slow-to-medium pace to give your body a chance to get ready for more vigorous movement. A warm up should last about 5 to 10 minutes.
Source:
National Heart, Lung, and Blood Institute
Water Intake
We all need to drink water. How much you need depends on your size, activity level, and the weather where you live. Keeping track of your water intake helps make sure that you get enough. Your intake includes fluids that you drink, and fluids you get from food.
Source:
NIH MedlinePlus
Weight (Body Mass)
Your weight is the mass or quantity of your heaviness. It is expressed by units of pounds or kilograms.
Source:
NIH MedlinePlus