Observations and results
What were your resting and exercising heart rates? How long did it take your heart rate to go back down to normal? Was it before or after you had caught your breath?
As you exercise more, your body gets more efficient and does not require as much heavy breathing or quick heart pumping. People who exercise regularly can do so longer without getting out of breath as quickly. They also tend to have heart rates that return to their resting levels more quickly after physical activity.
But of course, oxygen is not the only substance the body needs. We also need food for fuel. When we eat food, some of it is broken down by the body and transformed into the energy that gets us moving (these energy units are known as "calories"). More food does not always mean more energy. It depends on the type of food you are eating and how your body breaks the food down. For instance, the body can break down sugar and other processed carbohydrates, such as white bread, quickly. But sustained energy is better gained from foods that are harder to break down, such as lean protein and whole grains.
While breathing at different rates helps control the amount of air the body uses, the amount of energy from food the body uses is controlled much differently. If the body gets way more energy (or calories) than it can burn off, it will often store it away as fat.
What are some ways you and your friends and family can get more physical activity every day?
Share your jumping heart rate observations and results! Leave a comment below or share your photos and feedback on Scientific American's Facebook page.
More to explore
"If a Person's Lung Size Cannot Increase, How Does Exercise Serve to Improve Lung Function?" from Scientific American
"Does Exercise Really Make You Healthier?" from Scientific American
"Your Heart & Circulatory System" overview from KidsHealth
"Target Heart Rate for Children" table from Horizon and Blue Cross Blue Shield
Wallie Exercises by Steve Ettinger, ages 4–8
The Amazing Circulatory System: How Does My Heart Work? by John Burstein, ages 9–12
Clean Dirty Water with the Sun
What you'll need
• Mixing bowl
• Plastic wrap
• Clear drinking glass (slightly shorter than the rim of the mixing bowl)
• Small round marble
• Sunny ledge or warm surface
• Warm water