In one sentence, describe what the following article is about:

The heart is one of the body's most important organs, and a well conditioned and healthy heart is a big part of overall well-being. A normal heart usually beats at between 60-100 times per minute. Your own rate should ideally be no faster or slower than this when resting, though some elite athletes beat below 50 per minute. Place the first two fingers of your right hand on the inside of your left wrist just below your thumb, over one of your major arteries. You should feel a pulse. Count the number of heart beats for 15 seconds and then multiply that number by 4 for your heart's beats per minute.  In general, a lower resting rate indicates that your heart is strong. Higher rates mean that your heart has to work harder to do the same amount of work – it is weaker and less efficient. Add 1 to your chronological age if your resting pulse rate is 100 beats per minute or more. Can you still touch your toes? Flexibility declines as we age and can be limited in older bodies by a number of factors like increased dehydration, changes in the chemical structure of tissues, loss of muscle fiber with collagenous fibers, and increased calcium deposits. Your flexibility will give you some sense of your overall health. Sit on the floor with your back straight, legs together, and arms out in front of you at shoulder level. Beside your legs, mark on the floor the point directly below your fingertips and then slowly reach forward, keeping your legs straight. Mark where your fingertips reach and measure the distance between the two marks in inches.  How far did you reach? The farther the better, as it shows that your body is still spry and youthful. Add one if you were able to reach less than 5 inches. Subtract one if you got 10 inches or more. Neither add nor subtract if you were between 5 to 10 inches. How strong are you? In general, people gain muscle up to the age of about 30. Afterwards, however, we start to slowly lose muscle mass and, hence, physical strength. People over 30 who are inactive can lose as much as 3% to 5% of their muscle mass per decade, and even the physically active lose some. This loss of muscle mass – called sarcopenia – means a loss of strength and mobility and, in the elderly, can increase the risk of frailty, falls, and bone fractures. Test your own strength. Do as many modified push-ups (on your knees) as you can without stopping, keeping your body in a straight line and lowering your chest within four inches of the floor. Keep going until you can do no more.  Like flexibility, more strength is better. If you were able to do a high number of push-ups, you probably have a good deal of muscle mass and physical endurance. Add 1 if you did less than 10 push-ups. Neither add nor subtract for 10-19. Subtract 1 if you did reached twenty push-ups. Subtract two for more than 30.

Summary:
Find your resting pulse rate. Test your flexibility. Test your strength.