Expert Answer: Is HIIT Better for Weight Loss?

Written by Mariana K. Pencheva-Yanev, CEP and Dr. Amanda R. Bonikowske, Ph.D.

What is HIIT?

High Intensity Interval Training (HIIT) is a type of exercise training which alternates between higher intensity exercise bouts separated by recovery periods of complete rest or light intensity exercise within the same workout session. HIIT exercise can be performed using any modality including body weight and intervals can range from 10 seconds to 4 minutes and rest period duration can be adapted based on training goals and fitness level.  HIIT is safe and well-tolerated for most individuals including some with chronic health conditions. Check out this podcast with Dr. Amanda Bonikowske for further discussion of the cardiovascular benefits of HIIT.

Is HIIT Better for Weight Loss?

With respect to weight loss, current science does not present strong, consistent evidence that either HIIT or Moderate Intensity Continuous Training (MICT) is superior for weight loss. HIIT performed twice per week improves cardiometabolic health and further benefit occurs when performed three times per week such as increased fat loss, lowering of LDL cholesterol, and improved mental well-being. A more comprehensive exercise program may include 2-3 days of HIIT in addition to MICT and other aerobic and strength training activities on the other days of the week.

What are the Benefits of HIIT compared to MICT?

• HIIT leads to greater improvements in cardiorespiratory fitness and functional capacity compared to MICT
• HIIT is a more time efficient way to improve fitness- similar fitness improvements require 40% less time compared to MICT resulting in shorter exercise sessions
• HIIT improves glucose tolerance and insulin sensitivity especially in people with pre-diabetes or type 2 diabetes
• HIIT increases fat metabolism
• HIIT decreases visceral fat, the fat accumulated around the organs, which is highly correlated with increased cardiometabolic disease risk, regardless of total body fat
• HIIT may be more enjoyable than MICT
• HIIT improves the pumping strength of the heart
• HIIT helps increase HDL (healthy) cholesterol

Do I need to see my doctor prior to starting HIIT?

While most people can exercise without visiting a doctor, a physician clearance to start HIIT may be recommended if:

• You are not exercising regularly
• You have new or ongoing health conditions such as heart or lung disease, kidney disease, diabetes, orthopedic limitations, or other health conditions that may interfere with your exercise and you haven’t had a wellness visit with your doctor in the last 6 to 12 months
• You have symptoms at rest or with daily activity such as chest discomfort, shortness of breath, lightheadedness or dizziness, felt faint or have lost consciousness, felt like your heart is racing or skipping beats

Successful, long-term weight loss is often accomplished by managing multiple lifestyle aspects- from diet and exercise to stress management and sleep habits. Therefore, it is important to acknowledge that even though exercise plays an instrumental role in weight loss and maintenance, it is only one piece of the puzzle. Exercise is often encouraged by clinicians and allied health professionals for managing not only body weight but other health risk factors; however, we often face different challenges such as finding time to exercise and committing to a long-term, sustainable exercise routine.

HIIT is a great addition to your exercise routine because it addresses many barriers to exercise, leads to significant cardiometabolic improvements, and provides endless variation so you’re bound to find something you enjoy. Whether you have a well-established HIIT program, or you’re just trying to increase your daily HIIT exercise snacks by briskly climbing up the stairs, or getting up for 30 seconds of lunges or squats every hour over the course of the day, HIIT can help you reach your fitness and wellness goals.

Have you tried HIIT?