Factors affecting Fitness

These, of course, are general guidelines.

Many things along the way can speed up or slow down your progress.

“How fit you are when you get started is one factor that I’ve personally seen affect people’s individual results timeline,” said Clayton.

The type of exercise you choose also matters and it will affect you differently if you are a beginner or coming off an illness or injury.

“If you’re not comfortable with exercise, or perhaps are being cautious because of an injury, you are going to get different results from walking for 90 minutes per day than someone who is already used to exercise and decided to try a HIIT [high intensity interval training] program,” said Kingsford.

Beginners, though, may progress faster simply because they are starting lower down the fitness ladder and require less exercise to challenge their body.

“Beginners see huge jumps in strength across the board every week with proper training,” said Fauci.

Of course, what you put into an exercise program also determines what you get out of it.

On a perceived exertion scale of one to 10, “if you only feel comfortable exercising at a level six, you are going to get different results than someone who is comfortable exercising at a level nine,” said Kingsford.

In a 2007 study in the Journal of the American Medical Association, researchers placed sedentary, overweight, or obese women into three groups — exercising at 50 percent, 100 percent, or 150 percent of the recommended energy expenditure level.

Women who worked out at the highest intensity level saw an 8 percent improvement in their cardiovascular fitness after six months. Those at the lowest intensity level saw a 4 percent increase in fitness.

An 8 percent increase in fitness doesn’t seem like a lot, but if you’ve been inactive for a long time, it can be huge.

If you crank up the intensity even more, you’ll get faster results.

“We see fitness results from our students within about two weeks,” Tina Angelotti, fitness director of Krav Maga Worldwide, told Healthline. “Our students work at very high levels of intensity in our Krav Maga self-defense, fitness, and fight classes.”

If you are a beginner, or new to higher-intensity workouts, you might need to work up to this level.

“If you work too hard too soon, you risk injury or quitting from the stress,” said Clayton. “But if you don’t work hard enough, you won’t see results. So find your balance and know that healthy and fit is not a race nor a destination.”