Risks and Safe Practice Of HIIT 

By Foluke Akinwalere. Freelance Health writer. Reviewed by: Oluwasola Samuel.

 

Image of an African bodybuilder.  Image source: Freepik

 

Highlights

• Improper HIIT exercise increases the risk of sprains, strains, and joint injuries.
• Overtraining can lead to exhaustion, muscle soreness, sleep disturbances, and lack of motivation.
• Intense sweating during HIIT leads to fluid loss, increasing the risk of dizziness and fatigue.
• Beginners should start slow, prioritise proper form, and gradually increase intensity to prevent injuries.
• Older adults can benefit from HIIT with low-impact exercises, longer rest periods, and proper joint safety precautions.
• People with health conditions should consult a doctor and modify workouts to suit their health status.
• Pregnant women can do HIIT with medical approval, focusing on hydration, controlled movements and avoiding burnout.

 

Introduction

High-intensity interval training (HIIT) is a workout method that involves short bursts of intense exercise followed by brief recovery periods. It can be as short as 10 to 30 minutes.

 HIIT is an effective way to burn fat, boost endurance, and improve heart health. It is a powerful workout method that delivers fast and efficient fitness results. If done incorrectly, it can do more harm than good. 

Many people, especially beginners, make common mistakes such as pushing too hard, neglecting proper recovery, skipping warm-ups, or using improper form, which can lead to injuries, fatigue, or even heart strain. Understanding these risks and learning how to avoid them can help you maximise the benefits of HIIT while staying safe.

 

Risks of Doing HIIT Incorrectly

Many people, especially beginners, make common mistakes like skipping warm-ups, pushing too hard, or neglecting proper form, which can negatively impact their health and fitness goals.

Potential risks of improper HIIT and how to avoid them

1. Increased Risk of Injuries

HIIT involves explosive, high-impact, and quick movements, which stress the muscles and joints. This results in injuries if not performed correctly. [1]

This can lead to common injuries such as:

• Sprains and strains
• Knees and ankle injuries
• Lower back pain
• Shoulder injuries

How to prevent injuries:

• Warm up properly: Always spend at least 5-10 minutes doing dynamic stretches and mobility exercises.
• Focus on form, not speed: Prioritise correct technique over how fast you complete the exercise.
• Modify exercises if needed: Use low-impact variations (e.g. steps-ups instead of jump squats)
• Wear proper footwear: Supportive shoes help absorb shock and protect your joints

Moreover, customising HIIT workouts based on your fitness levels can reduce the risk of injuries. [1]

2. Overtraining and Burnout

Some people believe that doing HIIT every day will speed up weight loss and fitness gains. The truth is, excessive HIIT can cause fatigue, burnout, and pain. 

Signs of overtraining are:

• Persistent fatigue and exhaustion
• Muscle soreness that doesn’t go away
• Trouble sleeping or feeling restless
• Loss of motivation or burnout

How to avoid overtraining:

• Limit HIIT to 2-4 sessions per week
• Schedule a rest day: Allow your muscles at least 24-48 hours to recover.
• Listen to your body: If you feel exhausted or weak, take a break.
• Alternate workouts: Combine HIIT with low-impact exercises like yoga, walking, or swimming

 

Risks of HIIT when done incorrectly

 

3. Increased Risk of Heart Strain

While HIIT is excellent for cardiovascular health, overdoing it can put too much stress on the heart, especially for people with pre-existing heart conditions.

Who should be cautious?

• Individuals with high blood pressure or heart disease
• People who experience chest pain, dizziness, or irregular heartbeats during workouts
• Those who are new to HIIT push themselves too hard too soon.

How to protect your heart

• Consult your doctor before starting HIIT if you have a heart condition.
• Start slow: Begin with low-to-moderate intensity and gradually increase.
• Take breaks: Rest for 30-60 seconds between high-intensity intervals to let your heart recover.
• Monitor your heart rate by using wearable technology to detect any abnormalities during HIIT sessions. [1]

4. Dehydration and Electrolyte Imbalance

HIIT workouts cause intense sweating, which leads to loss of fluid and electrolytes. Drink the right amount of water to avoid muscle cramps, dizziness, or fatigue.

A useful suggestion is to drink a small quantity of water (150- 300mL) every 15 to 20 minutes during exercise, adjusting the amount based on how much you are sweating. Maintaining a fluid replacement rate that closely matches your sweat loss helps keep body temperature, heart rate, and effort level at their lowest levels. [2] Drink water before, during, and after HIIT exercises.

5. Muscle Loss Instead of Muscle Gain

If HIIT is done without proper nutrition and recovery, it can lead to muscle breakdown.

Why does this happen?

• Not eating enough protein after HIIT
• Doing too much HIIT without strength training
• Skipping rest days, preventing muscles from recovering

How to prevent muscle loss:

• Eat a protein-rich meal after HIIT: This helps repair and grow muscles.
• Balance HIIT with rest and recovery: Give muscles time to heal.
• Incorporate strength training by adding weightlifting to prevent muscle loss.

 

Is HIIT Safe for Everyone?

HIIT offers incredible benefits, but it may not be suitable for everyone in the same way. Factors such as age, fitness level, pre-existing health conditions, and injury history all play a role in determining whether someone should do HIIT and how they should approach it.

Let’s explore who can safely do HIIT, who should be cautious, and what modifications can make HIIT workouts more accessible.

1.  Can beginners do HIIT?

Yes! Beginners can do HIIT. However, they need to start at a manageable pace. It can be adapted to suit all fitness levels, including beginners.  Jumping straight into an intense routine without proper preparation can lead to injury, burnout, or excessive fatigue.

How to make HIIT safe for beginners:

• Start slow: Instead of doing high-impact moves like burpees, beginners can begin with low-impact alternatives like step-ups or controlled bodyweight squats.
• Increase intensity gradually: Begin with shorter intervals (30 seconds of workout) and progress over time.
• Focus on form first: Performing exercises with proper technique is more important than speed or intensity.
• Listen to your body: If an exercise feels too difficult, it is okay to modify or take extra rest.

2.  Is HIIT safe for older adults?

Older adults can greatly benefit from HIIT, but caution is necessary. [3] As you age, muscle strength, joint flexibility, and cardiovascular endurance naturally decline.  It is important to modify workouts as needed to suit your current fitness level to prevent strain or injury.

How to make HIIT safe for older adults:

• Choose low-impact exercises: Instead of jumping exercises, seniors can do marching in place, chair squats, wall push-ups, and slow step-ups.
• Prioritise joint safety: Movements should be controlled and smooth to avoid unnecessary stress on the knees, hips, and lower back.
• Ensure adequate recovery: The rest period should be longer to allow for proper recovery between exercises.
• Check with a doctor: Older adults with conditions like high blood pressure, arthritis, or heart disease should consult a doctor before starting HIIT.

3.  Can people with health conditions do HIIT?

For individuals with chronic conditions like high blood pressure, diabetes, heart disease, asthma, or respiratory issues, HIIT can be beneficial if done correctly and under medical supervision. It is important to consult a doctor before starting any exercise and modify workouts to match your fitness level.

Health conditions and HIIT considerations:

• High Blood Pressure:  HIIT can improve heart function, but people with hypertension should avoid extreme effort and opt for moderate-intensity intervals instead.
• Heart Disease:  People with heart conditions should get medical clearance before starting HIIT. A safer approach is low-intensity interval training with longer recovery periods.
• Diabetes:  HIIT helps control blood sugar, but diabetics should monitor their blood sugar levels and avoid workouts on an empty stomach to prevent dizziness.
• Asthma or respiratory issues:  HIIT can improve lung capacity, but individuals should choose exercises that don’t trigger breathing difficulties and ensure proper warm-up and cool-down routines.

4.  Can pregnant women do HIIT?

Pregnant women can safely engage in exercise. A recent study found that HIIT was well tolerated by pregnant mothers and babies. [4] However, a doctor or prenatal fitness expert should be consulted before attempting any form of HIIT during pregnancy to avoid the risk of injury, dehydration, and overtiredness.

How to modify HIIT for pregnant women:

• Lower the intensity: Instead of fast, explosive movement, choose controlled, steady exercises like bodyweight, squats, or slow matching in place.
• Avoid high-impact exercises like jumping. The impact can strain the joints and pelvic floor.
• Stay hydrated and avoid overheating
• Listen to your body.

5.  Is HIIT safe for people recovering from injuries?

People recovering from injuries should approach HIIT with caution. While HIIT helps with strength and rehabilitation, doing the wrong movements can worsen injuries or delay recovery.

How to make HIIT safe for injury recovery:

• Avoid high-impact movements
• Use supportive equipment
• Focus on controlled movements instead of fast repetitions
• Consult a physical therapist for safe modifications for specific injuries.

 

Tips for Practicing HIIT Safely

• Choose the right workout environment: Opt for well-ventilated spaces, shaded areas, or indoor workouts during extreme heat to prevent heat exhaustion.
• Wear appropriate clothing: Light, breathable clothing helps regulate body temperature, while proper footwear prevents injuries and supports movement.
• Listen to your body: Avoid overexertion. If you feel dizzy, nauseous, or extremely fatigued, take a break and adjust your workout intensity accordingly.
• Modify workouts when necessary: For beginners, the elderly, or those with medical conditions, lower-intensity versions of exercises reduce strain while still providing benefits.
• Warm-up and cool down: Stretching before and after workouts reduces the risk of injury and helps muscles recover faster.

 

Conclusion

HIIT can be an excellent way to improve fitness, burn fat, and boost endurance—but only when done correctly. Avoiding common mistakes like skipping warm-ups, neglecting form, or overtraining can help prevent injuries and long-term health issues. If you are new to HIIT or have any health concerns, consult a fitness professional or doctor for guidance. Listen to your body, modify workouts when needed, and ensure proper recovery after each session to help you enjoy the full benefits of HIIT safely.

 

References

1.  Plizga, Jakub & Jaworski, Arkadiusz & Grajnert, Filip & Gluszczyk, Agnieszka & Surma, Alicja & Cecot, Jakub & Parfianowicz, Agnieszka & Zarzecki, Konrad & Mandryk, Mi?osz & Holdun, Nazar. (2024). High-Intensity Interval Training - health benefits and risks - literature review. Quality in Sport. 18. 53359. 10.12775/QS.2024.18.53359. Available from here

2. Latzka WA, Montain SJ. Water and electrolyte requirements for exercise. Clin Sports Med. 1999 Jul;18(3):513-24. doi: 10.1016/s0278-5919(05)70165-4. PMID: 10410838.Available from here

3.  Marriott CFS, Petrella AFM, Marriott ECS, Boa Sorte Silva NC, Petrella RJ. High-Intensity Interval Training in Older Adults: a Scoping Review. Sports Med Open. 2021 Jul 19;7(1):49. doi: 10.1186/s40798-021-00344-4. PMID: 34279765; PMCID: PMC8289951.Available from here

4.  Wowdzia JB, Hazell TJ, Berg ERV, Labrecque L, Brassard P, Davenport MH. Maternal and Fetal Cardiovascular Responses to Acute High-Intensity Interval and Moderate-Intensity Continuous Training Exercise During Pregnancy: A Randomized Crossover Trial. Sports Med. 2023 Sep;53(9):1819-1833. doi: 10.1007/s40279-023-01858-5. Epub 2023 May 22. PMID: 37213048. Available from here 

 

 

Related 

High-Intensity Interval Training: A Better Fitness Approach for Africans

Weekend Exercising is as Beneficial for Health as Daily, Study Says

7 Tips for Sustainable Exercise for Beginners in Africa 

Best Exercise for Healthy Ageing in Africans (Tips)

Exercising in Natural Surroundings More Beneficial Than Indoors, Study

Exercising When Sick: Good or Bad, and Safety Tips to Follow

8 Best Gym Hygiene Practices for Africans

 

 

Published: March 20, 2025

© 2025. Datelinehealth Africa Inc. All rights reserved.

Permission is given to copy, use and share content freely for non-commercial purposes without alteration or modification and subject to source attribution.