Jan. 3, 2014 at 1:52 PM ET
You know how many candles you blew out on your last birthday, but that doesn't tell you what your fitness age is.
There are a number of ways to determine your physical health, from measuring your BMI to stepping on a scale. But they don't reveal your fitness age, says Michelle Bridges, an Australian trainer, author and creator of the "12 Week Body Transformation Program." Fitness age, according to Bridges, is partly determined by how well your body delivers oxygen to your cells. "It's a great indicator of your overall health," Bridges told Matt Lauer Friday.
Fitness age can be affected by your chronological age, activity level, as well as your waist and resting pulse rate. The goal is to have your fitness age lower than your birth age. On Friday, Bridges had some surprises for the TODAY team — including Lauer, 56, and Al Roker, 59 — when she revealed their "fitness ages" and gave advice on how to improve or maintain them.
Try the tips Michelle offered to the TODAY team to help improve your own fitness age:
Bicycle crunches are a bit harder than standard ab crunches. They tend to work the lower abs more. Good for working on your waistline.
The plank exercise is a great way to build endurance in both the abs and back, as well as stabilize the muscles and physique you already have. This exercise requires a lot of core strength.
This is a mix of cardio, strength training and quad toning. Good for overall fitness and will help you lose weight.
These help strengthen your back, shoulders, biceps and triceps. This exercise will also help shrink your waistline and lower your resting heart rate.