High-intensity interval training is a perfect way to upgrade your fitness. It’s a mode of exercising that focuses on power and intensity. What you are guaranteed to have after each step in HIIT workout is an increased heart rate.

Most gym fanatics are interested in this sort of workout because it enables them to do more in a little time. With high-intensity exercising they force their body to go through a process that keeps working on their body even several hours after workout, which is amazing.

But people need to know that such intense workout is not always good. HIIT although is a powerful instrument and any healthy human can practice it but here are some factors to keep in mind when organizing your workout around such high intensity workout routine. Doing HIIT more than two to three days a week without a 24 hours gap in-between can do more harm than benefit to the body.

Listed below are a few disadvantages of overdoing HIIT:

1. Higher chance of injury

With high intensity comes a higher risk of damage. HIIT is a powerful workout, and thus it requires a lot more movement than other exercises. During HIIT, a beginner might lose control over his body and get injuries. During burpees, you might get damage your knees. Running at high intensity might be hard on your whole body. The best option is to do a warm-up before starting a workout and don’t always test your limits. No pain no gain is only a myth.

2. Stress on Muscles and Joints

Different interval durations and intensities can lead to diverse physiological damages. Longer intervals with high intensity result in higher acute cardio-circulatory responses. Running at full speed causes muscle damage and soreness. Do as much as your body can tolerate. There is always another day to come back and workout again. Don’t put so much stress on your muscles and joints that you can’t move them the next day. Make exercising a part of life that enables you to live healthily, not an activity that keeps you in bed the next day.

3. Stress on Body

During HIIT, you might trigger cortisol which is the stress hormone. It results in extra stress on the body that develops gastrointestinal diseases, for instance, Inflammatory Bowel Disease (IBD) and Irritable Bowel Syndrome (IBS). If you are working out too heavily, you will naturally build a fatigue that will stop you to touch the exercise equipment the next day. Don’t put so much stress on the body that your mind is unable to go for the next drill on next day.

4. Weakening of Immunity

Doing excessive intense workouts can make you ill. If you practice HIIT more than 3-4 times a week, it will make your immune system weak, and you eventually can fall sick. However, regular physical activity boosts your natural defense mechanism and might help you with HIIT.

5. Decline in Mitochondrial Functioning

Mitochondria are also known as the powerhouse inside the cell. Sometimes, HIIT damages it so bad. According to an admonitory new study of the molecular effects of HIIT, people who started working out with great energy developed acute declines in the performance of mitochondria and symptoms of blood sugar dysfunction.

In one more study, people who practiced HIIT routines three times a week failed to improve their blood pressure or body fat.

6. Higher Susceptibility to Over training or Burn Out

Excess of everything is terrible, be it eating or exercising. High-intensity interval training demands too much physical and psychological energy that puts you at the risk of overtraining or burnout. Overtraining is a state in which excess exercise leads you to get an injury or fall ill. When we try to advance too quickly, our body hardly gets time to adapt appropriately. So you are more likely to be unwell for a long time.

7. Loss of Appetite and Sleep

HIIT is considered an ideal workout for building strength and fitness. However, it might affect your sleep, mood, and energy badly. Individuals who practice high-intensity interval training regularly tend to achieve baseline cortisol levels.

Cortisol is good for body repair until you gain a flat cortisol level which eventually causes mood swings, loss of sleep and appetite. In terms of mood swings, flat cortisol is also associated with increased fatigue, a high level of depression, and low self-esteem. It’s significant to note that you can elevate cortisol due to non-exercised induced stresses. So, if you’re just already stressed due to daily life, avoid practicing HIIT.

8. Plateau or Drop-in Training Progress

Some research points out that if you practice HIIT around 8-10 hours per week and consume longer than 30-40 minutes a week, it can have a destructive impact on your workout performance – resulting in a plateau or drop in training progress. But what was particularly interesting is how this optimal dosage correlates with these broader health indicators.

9. Depletion of Glycogen

During the workout, the body first employs fuel that is available for quick processing. Firstly, free-circulating sugar goes into the blood and utilizes glycogen (carbohydrates in the liver and muscles). The human body restores glycogen during rest; however, during HIIT, you cannot replenish them.

If you perform HIIT frequently, it could result in a decreased amount of glycogen, leading to gluconeogenesis. Gluconeogenesis is a metabolic process of transforming protein to generate glycogen; it restrains the amount of protein required to repair muscle tissues that are impaired by rigorous exercise.

10. Demotivation

You need the motivation to practice any exercise. Especially, HIIT requires a lot of energy and demands too much of your body. Excessive intensity eventually leads to burnout and demotivation. If you overplay high-intensity training, you will find yourself scared of doing it for a long time and end up quitting it. So, the best option is to opt for a bit easier workout routine.

11. You must avoid HIIT if you are:

Heart Patient

During HIIT, your muscles require extra oxygen because a high intense workout places a lot of burden on your heart. Your body has to perform additional work that results in extra pressure on the nature and cardiorespiratory system. If you suffer from heart problems, HIIT can be extremely risky for you.

Not Sober

HIIT is not for you if you drink alcohol. You might get severe injuries if you practice HIIT in a hangover.

New to Workout

When you are at the preliminary stages of a workout, HIIT is not a good option. In the beginning, your muscles are not strong enough to handle high-intensity training, and if you start this training, you might strain your muscles. It would help if you made your body used to exercise and then move to such high-intensity activity.


HIIT puts a lot of stress on muscles and joints. If you are injured and start doing high interval training, you might make your injuries complicated.

Bottom Line

HIIT is a great option to choose if you do not have much time for a workout, and it presents vast results regarding weight loss and overall fitness if you use it inappropriate way. Warning about HIIT might seem pessimistic approach. However, the whole concept is to warn people about the possible risks. You might end up hurting yourself if you do not have proper guidance about the right way to adopt HIIT. You also need to add gentler exercises in your workout routines when you cannot perform high-intensity workouts. It will help you in losing weight while maintaining your health.

Categories: Fitness

Arshia Ubaid

I'm a Biochemistry Graduate of Islamia University Bahawalpur. An enthusiastic content writer who is eager to contribute to team success through hard work. Motivated to learn, grow, and excel in my field.