Obesity is a widespread health concern, contributing to cardiovascular and metabolic disorders, and elevating the risk of mortality. Lifestyle modifications, particularly exercise, play a crucial role in obesity treatment, offering benefits beyond weight loss, such as improved cardiorespiratory fitness (CRF). While moderate-intensity continuous training (MICT) has been a traditional recommendation, high-intensity interval training (HIIT) has emerged as a time-efficient alternative. This article delves into the effectiveness of HIIT for weight loss, comparing it to MICT and exploring its various benefits and limitations.
Understanding HIIT and MICT
High-Intensity Interval Training (HIIT)
HIIT involves short bursts of high-intensity exercise alternated with periods of low-intensity exercise or rest. This method allows individuals to achieve similar results to traditional cardio in a shorter amount of time. For example, a HIIT workout might consist of 3-7 repetitions of 3 minutes at 100% of maximal oxygen uptake (VO2peak) interspersed by 1.5 minutes at 50% of VO2peak.
Moderate-Intensity Continuous Training (MICT)
MICT involves sustained exercise at a moderate intensity, typically around 60% of maximal oxygen uptake (VO2max). Guidelines often suggest at least 225-420 minutes of MICT per week to achieve significant weight loss.
Comparing HIIT and MICT for Weight Loss
A study involving 44 obese subjects compared the effects of HIIT and MICT over 12 weeks. The subjects were randomized and trained with isoenergetic treadmill exercises. The results showed that both HIIT and MICT had comparable effects on weight loss, changes in fat mass, fat-free mass, diastolic blood pressure, and low-density lipoprotein cholesterol. Specifically, weight loss was −6.0 kg for MICT and −5.7 kg for HIIT.
However, there was a significant difference between the groups in VO2peak (HIIT: +461.6 mL; MICT: +170.5 mL) and the duration of sessions (HIIT: 35.0 min; MICT: 46.5 min). These findings suggest that HIIT could be at least as effective as MICT, offering a time-saving exercise mode with superior improvements in CRF.
Read also: Comprehensive HIIT Guide
Benefits of HIIT
Time Efficiency
HIIT allows individuals to accomplish equicaloric training sessions in significantly less time, up to 40% less than MICT.
Comparable Weight Loss
Studies indicate that HIIT is at least non-inferior to MICT in terms of changes in body weight and may even be superior in reducing body fat. A recent meta-analysis supports that HIIT is as effective as MICT in inducing weight loss and body composition modification.
Improved Cardiorespiratory Fitness
HIIT induces greater improvements in CRF compared to MICT.
Cardiometabolic Benefits
HIIT may offer superior benefits in addressing cardiometabolic disorders.
Metabolic Rate Boost
HIIT can boost your resting metabolic rate, leading to calorie burning for up to 24 hours after your workout.
Read also: Comprehensive HIIT Guide
Limitations of HIIT
Intensity
HIIT is an extreme type of workout program that builds endurance, strength and helps shed weight more quickly than low-intensity cardio.
Diet
HIIT can assist you in dropping the weight, as long as it’s combined with a low-calorie diet or nutrition plan.
Not for Everyone
HIIT may not be the best choice for those who are new to exercise or who have joint issues.
Overdoing It
HIIT workouts are hard on the body and should be alternated between less intense workouts like walking or yoga to avoid injury.
Practical HIIT Workout Examples
Tabata
Consists of eight rounds of 20 seconds of intense exercise followed by 10 seconds of rest. Exercises can include squats, push-ups, and burpees.
Read also: Weight Loss Guide Andalusia, AL
Circuit Training
Involves performing a series of exercises quickly with minimal rest in between. This type of workout typically includes a combination of strength-training exercises and aerobic activities to provide a full-body workout.
Sprint Intervals
Involve alternating between short bursts of maximal effort sprints and periods of active recovery. For example, running at maximum speed for 30 seconds followed by a one-minute recovery jog.
Factors Influencing HIIT Results
Caloric Deficit
Maintaining a calorie deficit is vital for shedding pounds.
Maximum Heart Rate
Understanding your maximum heart rate during exercise plays a role in optimizing weight loss through HIIT. Calculating your maximum heart rate (220 minus your age) allows you to determine target heart rate zones that promote fat-burning efficiently.
Insulin Sensitivity
HIIT can positively impact insulin sensitivity, which is crucial for weight management.
Age, Gender, and Genetics
Age affects the rate at which individuals see results from their workouts, including those involving HIIT. Gender differences may also influence how quickly one sees results from HIIT.
Additional Research and Studies
Zhang et al. (2017)
A study on 43 healthy Chinese female participants found that a 12-week HIIT program of 4-min work alternating with 3-min passive recovery attained comparable body composition and aerobic capacity results in half the amount of time it took for a continuous exercise group.
Heydari, Freund, and Boutcher (2012)
This study found that an exercising HIIT group saw significant reductions in all body fat parameters measured. Aerobic capacity, as measured by maximal oxygen consumption tests improved 15% from the HIIT intervention.
Talania et al. (2006)
Results indicated that 7 sessions of HIIT over a 2-week period resulted in marked increases in whole body and skeletal muscle capacity for fatty acid oxidation in the moderately active women.
Jacobs et al (2013)
Study results indicate that HIIT offers meaningful benefits in reducing abdominal and total body fat in 50% of the time as compared to steady-state training programs.
Personal Experiences with HIIT
One individual shared their experience of using HIIT workouts during a challenging time, noting improvements in posture, self-confidence, and resting heart rate. They emphasized that HIIT helped them come out of a difficult period in better shape than they were going in.
Incorporating HIIT into Your Routine
Consistency
Pick a form of exercise you enjoy participating in and be consistent, even when you don’t see results.
Variety
Mix up your routine with strength training and cardio on other days for maximum results.
Realistic Goals
Set realistic goals and find someone who can keep you accountable, such as a trainer, support group, or team.
Building Muscle
As you build more strength and muscle, you'll end up burning more calories 24/7, as muscle burns more calories than fat.