Cardiovascular Effects of High-Intensity Interval Training (HIIT)

It is estimated that one-third of the adult population in the United States has blood
pressure values that are classified as prehypertension. This slight elevation in blood
pressure has been shown to result in an increased risk for developing hypertension and
cardiovascular disease. The Seventh Report of the Joint National Committee on Prevention,
Detection, Evaluation, and Treatment of High Blood Pressure (JNC7) recommends lifestyle
modifications for individuals classified as prehypertensive. One lifestyle modification
suggested by JNC7 is regular physical activity. Aerobic exercise, like moderate-intensity
continuous training (MCT), has been shown to improve blood pressure, blood vessel function,
and arterial stiffness in those with prehypertension. However, a major barrier to exercise
adherence is the time commitment required. High-Intensity Interval Training (HIIT), which
requires individuals to work at higher intensities for shorter durations, may offer an
alternative training design that would reduce the time commitment. Previous studies have
shown HIIT to be equal to or better at improving cardiorespiratory fitness and blood vessel
function in multiple populations. Limited information is present on HIIT training in those
with prehypertension. In this study, participants will be randomized into one of the two
training program designs mentioned above (MCT or HIIT). Both programs will be completed over
an 8-week period (3 sessions per week) and each training session will be supervised.
Participants will complete testing visits before and after the training program to collect
measures of cardiovascular health (exercise capacity, blood pressure, blood vessel function,
and blood pressure reactivity). The goal is to compare the effects of the training programs
on these measures of cardiovascular health.

Inclusion Criteria:

- Blood Pressure less than 140/90 mmHg

- Sedentary

Exclusion Criteria:

- Known or major signs/symptoms of cardiovascular, pulmonary, renal, or metabolic
disease

- Cancer

- Use of antihypertensive medication

- Current tobacco use

- BMI (body mass index) less than 30 kg/m2

- Postmenopausal

- Current pregnancy

- Current hormone replacement therapy

- Participating in regular aerobic exercise at least three times a week for 30 minutes
at a moderate intensity for the past 3 months or more

- Not able to regularly exercise for any reason