What is HIIT? HIIT stands for High Intensity Interval Training. These workouts generally combine short bursts of intense exercise with periods of rest or lower-intensity exercise. Often, the instructor will say things like, “You can do anything for 30 seconds!” These helpful prompts remind you that after those 30 seconds, you’ll enjoy a 10 or 15 second break. The length of the exertion and breaks change but the concept is the same. You’re aiming for “all out” effort while you’re doing the move or lift and the immediate reward is a rest period that breaks up the “work” of the workout. 

Why is HIIT popular? In our ever diminishing free time, Americans are looking to maximize the time they have to work out and make sure it’s as efficient as possible. Simply put, “Why run for 50 minutes if you can get the same benefits in a 25 minute HIIT routine?

Also, workout burnout is real. HIIT workouts are as varied as one’s trainer’s imagination and they can be done at home, in the gym or outside. 

What about my heart? HIIT has specific heart benefits? 

Short answer: Yes and science backs it up. Let’s dive in. 

1) HIIT improves stroke volume 

Stroke volume is the amount of blood pumped around the body per heartbeat. Stroke volume increases during exercise, especially during demanding forms such as a HIIT workout because of the body’s increased need for oxygen-filled blood. When your body is using oxygen more efficiently, every day tasks become easier. 

Related to stroke volume, is the benefit HIIT has on your blood’s circulation. As the blood circulates, it delivers oxygen and nutrients to the body’s cells and takes away waste products.

Increased blood circulation helps cells grow and organs function properly, including your heart. When your circulation increases, the heart muscles relax and your blood pressure goes down. 

2) HIIT lowers your resting heartrate

The resting heart rate for an adult typically varies between 60 and 100 beats per minute. But an athlete’s heart is bigger and stronger and, therefore, needs far fewer beats to do its job. Simply put, it’s less taxing and more efficient on your heart if it doesn’t have to beat as much.  

A British Sports Journal study was done to assess the effect and comparison of high-intensity interval training (HIIT) versus moderate intensity continuous training (MICT) representing the same total training load on resting HR and BP in coronary artery disease (CAD). Twelve CAD patients were randomly chosen to do either HIIT workouts for 33 min or MICT for 41 min, three times a week for 8 weeks. The result showed that the resting heart rate and the systolic and diastolic blood pressure decreased with the HIIT participants. 

Heart disease is a great equalizer since its the leading cause of death for men, women and people of most racial and ethnic groups in the U.S. Source: https://www.cdc.gov/heartdisease/facts.htm

However, the relationship between heart disease and women is much more complicated since women’s symptoms and risk factors are unique

3) HIIT Can Improve A Sluggish Metabolism 

An imbalanced metabolic system can cause Metabolic Syndrome. According to Dr. Abby Bleistein, “Metabolic syndrome is defined by a set of findings: Elevated triglycerides, high blood sugars, elevated waist circumference, high blood pressure. It is a precursor to type II diabetes and represents an increased risk of cardiovascular disease.  People with metabolic syndrome are insulin resistant.” People with Metabolic Syndrome are 3x more likely to suffer from heart disease thanks to the insulin resistance it causes. 

A study published in Cell Metabolism looked at 32 people in their 50’s with Metabolic Syndrome who participated in HIIT.  Their results showed a 35% increase in aerobic fitness compared to a 16% increase in those who did continual moderate exercise. 

4) HIIT Can Increase “Good” Cholesterol

Simply put, cholesterol is a type of fat found in your blood. Low-density lipoprotein (LDL) is known as the “bad” cholesterol. LDL can build up in your arteries and form fatty, waxy deposits called plaques. When the plaque builds up inside a coronary artery, blood flow to the heart is compromised. The result? A heart attack. 

To remember which is which, think LDL you want L-O-W. The yang to LDL’s ying is HDL, high-density lipoprotein aka “good” or “healthy” cholesterol. HDL is responsible for the transport of cholesterol from the artery walls to the liver, where it is converted to bile and used for digestion or disposed of.   An analysis of 14 studies that looked at cholesterol levels and HIIT show that HIIT has been shown to improve HDL cholesterol after a minimum of 8 weeks of training. 

To sum up, HIIT is the antithesis of a repetitive workout and when our mind is stimulated it makes it easier to keep doing something. HIIT workouts can be done in the privacy of your home on your schedule and if you’re time pressed, you can still benefit from their heart racing benefits. Finally, HIIT workouts have specific heart related benefits so why not take them up in Heart Healthy February and continue them throughout the year? 

Healthful Life MD’s medical team monitors indicators of heart disease and works in conjunction with a personal trainer to design the most efficient and effective workouts that you will want to keep doing. To find out more about the workouts and how we assess your heart’s health, schedule a time to talk with Dr. Abby Bleistein. Schedule a free call