Exercise group participants will perform supervised high intensity exercise three times per week at the LLU department of physical therapy laboratory utilizing treadmills, stationary bicycles, and rowing machines.

Control group participants will make no modifications to regular diet or exercise habits for 30 days.

Participants will rotate between three exercise machines (randomly assigned rotation order at outset): A Concept C2 rowing machine, a stationary bicycle, and a treadmill. Study participants will use a different machine each day so that they are using each of the three exercise machines once per week. Two treadmills, two bikes, and two rowers are available during each exercise session. Participants will be randomly assigned to one of three machine orders: treadmill-rower-bike, rower-bike-treadmill, or bike-treadmill-rower. We will employ a percent of heart rate protocol as an exercise intensity measure (77-93% of age-adjusted maximum heart rate) rather than a less well-defined maximal effort protocol or rating of perceived exertion scale. For the purposes of this exercise protocol high intensity exercise will be defined as 77-93% of age adjusted maximum heart rate.

Participants will have 8ml of blood drawn on two separate occasions by a certified phlebotomist. The first 8 ml (1.62tsp) blood draw will occur at 8am on day 1 of the study protocol. The second 8ml (1.62tsp) blood draw will occur approximately 30 days later. The total blood draw volume will be 16ml or approximately 3.25 teaspoons. The blood draw is to test for the effects of exercise on gene expression and aging.

The most widely used psychological instrument for measuring the perception of stress. It is a measure of the degree to which situations in one's life are regarded as stressful during the past 30 days. Responses are scored from 0 to 4. And the total score can be from 0 to 40.

"Scores ranging from 0-13 would be considered low stress. Scores ranging from 14-26 would be considered moderate stress. Scores ranging from 27-40 would be considered high perceived stress."