High-Intensity Interval Training (HIIT): Pros and Cons

Introduction

HIIT is booming in popularity today. Recent studies show that people undertaking High-Intensity Interval Training at least twice a week rose from 1.9 million to 2.4 million last year. 

HIIT workouts are designed to push you to your limits through intense bursts of exercise followed by brief recovery periods. These training exercises are vigorous enough to deliver results faster than regular workouts, making them suitable for people who find it challenging to take time out for exercise. 

HIIT offers both cardiovascular and strength benefits without you having to spend long hours at the gym. 

It can be performed with a few basic pieces of equipment, and so it is accessible to a wide audience, from gym-goers to those training at home.

So if you are aiming to lose weight, build endurance, or just shake up your fitness routine, choose a HIIT workout that is sure to deliver the results you are looking for. 

How HIIT Exercises Work

High-Intensity Interval Training as the name suggests, means short bursts of intense exercise with brief recovery periods in between. 

The aim of HIIT exercises is to push your heart rate into a high-intensity zone (usually 80–90% of your maximum heart rate) where your body is forced to work harder than in regular cardio. You burn calories faster during and even after you have completed your HIIT workouts.  This is because excess post-exercise oxygen consumption, also known as the “afterburn effect”, is still going on. 

So what does a typical session look like? 

You can start with an exercise like sprinting, cycling, or bodyweight exercises (like burpees or jumping jacks) at full effort for a short period, followed by an equally short recovery or rest period.

This pattern is repeated throughout the HIIT workout, often lasting between 10–30 minutes. 

The intensity of this workout makes it effective for both cardio and muscle endurance and can be adjusted to suit different fitness levels by varying the intensity, exercise choice, and duration.

Benefits of HIIT Workout

Here are some of the main advantages:

• Time Efficiency

HIIT workouts are perfectly suited to those fitness enthusiasts who are pushed for time. As a typical session lasts between 10–30 minutes it is ideal for people with busy schedules. This means you can achieve a high-calorie burn and cardiovascular benefits in a fraction of the time compared to traditional workouts.

• Increased Calorie Burn

The intense nature of these sessions means you end up burning more calories. Additionally, the “afterburn effect” keeps your body burning calories even after the workout is over.

• Improved Cardiovascular Health

HIIT challenges the heart by pushing it to work harder during intervals. This can improve blood flow, reduce blood pressure, and strengthen heart health.

• Enhanced Fat Loss and Metabolic Rate

Studies have shown that it can be particularly effective in reducing body fat, especially visceral fat. 

• Increased Muscle Tone and Endurance

HIIT often involves bodyweight or weighted exercises, allowing for the development of muscle tone. It can also improve muscle endurance, as the intense intervals push muscle groups to their limits.

• Improved Insulin Sensitivity and Blood Sugar Regulation

Regular HIIT can improve insulin sensitivity, which helps the body use glucose more effectively. 

• Versatility and Adaptability

This form of exercise can be adapted to different fitness levels and preferences, from running and cycling to bodyweight exercises like squats and push-ups. This makes it suitable for beginners and advanced athletes alike.

• No Equipment Needed

Many HIIT workouts can be done without equipment and at home, relying on bodyweight exercises like burpees, lunges, and sprints. 

These benefits make it an appealing option for many fitness enthusiasts, offering a highly efficient, effective workout that supports cardiovascular health, fat loss, muscle tone, and mental well-being.

Drawbacks of HIIT Exercises

Although HIIT offers many benefits, it also has some drawbacks you should consider:

• Risk of Injury

The high intensity and repetitive nature of these movements can lead to a greater risk of injury. Fast-paced moves like burpees or jump squats can place a lot of strain on the joints and muscles which can result in strains or sprains.

• Physical Exhaustion and Overtraining

HIIT can be physically demanding and can push the body and if done too frequently, it can lead to overtraining, fatigue, and burnout.

• Not Suitable for All Fitness Levels

It is often recommended for those with at least a basic level of fitness, as the high-intensity intervals require a strong cardiovascular and muscular foundation. Beginners or people with certain health conditions may find it too challenging or unsafe, especially if they are unable to maintain proper form during rapid movements.

• Increased Stress on the Heart

While HIIT can improve heart health, it can also be stressful for the heart if done improperly or too much. People with heart issues or high blood pressure should practice it cautiously and ideally consult a healthcare professional before starting.

• Potential for Muscle Loss

If not balanced with strength training, this workout can contribute to muscle loss over time, especially if it is heavily cardio-focused without enough emphasis on resistance work. For those aiming to build muscle mass, HIIT alone may not be sufficient.

• Mental Strain and Burnout

The intensity of these workouts can be mentally challenging, and some people may find it difficult to stay motivated with such high-demand sessions. Over time, this can lead to mental burnout or aversion to exercise altogether.

• Potential to Raise Cortisol Levels

It can increase cortisol levels, especially if done too frequently without adequate amounts of rest. If there are raised levels of cortisol in the body, there is a strong chance of recovery being hindered.

Who Should Try HIIT?

• It is ideal for people with an intermediate or advanced fitness level due to its intense structure. 
• Beginners can try versions that are better suited to their requirements and moulded to their fitness levels. The key for them is to progress gradually.
• People with heart issues, joint problems, or other medical concerns should approach it with caution. 
• Consulting a healthcare provider before starting is highly recommended, especially for older adults or those with certain health conditions.

Best Practices for HIIT

1. A proper warm-up is important to prepare the body and a cool-down is needed to aid recovery and prevent stiffness.
2. You must monitor form and intensity especially when fatigued, to prevent injuries and to maximise effectiveness.
3. Adopt the optimal frequency of 2-3 sessions per week.
4. For balanced fitness, alternate with other types of workouts, such as strength training or cardio.
5. It is encouraged to have adequate rest days to give muscles time to recover, reducing the risk of overtraining and injury.

Final Word

So even if HIIT offers a range of benefits, and is a time-saving workout certain things need to be considered. The intensity and demands of this exercise can bring potential drawbacks, including an increased risk of injury, greater recovery needs, and the possibility of overtraining. 

This workout can therefore be a powerful tool when balanced with other types of exercise and approached with proper preparation. If you do choose this form of workout, keep your fitness level, personal goals, and health conditions in mind. When done mindfully, HIIT can support a well-rounded fitness routine and deliver outstanding results.

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