Sex And Cardio: How Your Gender Affects Your Cardio Workouts

Rise of the HIIT training

Cardiovascular or 'cardio’ training has become a staple in many people's exercise routine. And, in the last few years High Intensity Interval Training, or HIIT, has become a huge craze, replacing the conventional long, steady-state training (i.e. putting in the miles on the treadmill) as the dominant form of working the heart and lungs, and, perhaps more importantly, in burning up calories to help with weight loss.

Both men and women have been turning in their running shoes for a pair of dumbbells and an interval timer, with many women preferring HIIT training to lower intensity routines. But should both men and women expect equal results from HIIT as from steady-state conventional training?

Indeed, four separate studies, all using different types of interval training and steady-state training all showed a very clear trend; that, when body weight and time was accounted for, women actually burned less calories when using HIIT type training than men, but generally outperformed men when exercising at lower intensities, a trend which, interestingly enough, seems to crossover to resistance training, as well.

On average, women who were completing HIIT workouts burned between 0.09 to 0.2 calories per minute per kilogram of bodyweight, whereas men went from 0.13 up to as high as 0.29 calories per minute per kilogram of bodyweight.

So, to put that in perspective, a normal 70 kilogram man who did 10 minutes of HIIT training could burn up to 203 calories, compared to just 140 calories for a woman who did HIIT for the same amount of time and weighed the same as her male training partner.

And if you're doing more than one HIIT workout per week, that gap in calories is going to multiply.

Slow and Steady wins the race

As stated above, the same group of studies that showed that men generally tend to burn more calories per minute at higher intensities, also showed that women tended to burn more calories per minute at lower intensities.

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In fact, in low intensity jogging as well as in walking, women burned 0.6 calories per minute per kilogram of bodyweight to men’s 0.5 and, during low intensity jogging, 0.16 calories to men’s 0.12, so that would mean that, in 30 minutes of running, a 70 kilogram woman would burn 336 calories, compared to 252 for a man of the same weight; a difference of almost 100 calories. In one workout!

But why is this?

It could be due to the fact that physically active women usually have a higher number of ‘endurance’ type fibers (known as Type 1 or ‘slow twitch’ fibers) than their male counterparts. This would cause lower intensity exercise to work more of the muscle in a more optimal way, and, hence, could cause greater energy being used for the exercise than if it was performed at a higher intensity, like in interval training.

HIIT vs. Low Intensity Workout: Conclusions and Recommendations 

This by no means is a call to ditch the Intervals if you’re a woman, HIIT training can be very effective for burning fat and improving fitness. However, those who claim that HIIT is a superior form of training for everyone may still have some research to do.

Another element to take into account is the phase of the menstrual cycle a woman is in. As has been shown in an article about menstrual cycle, nutrition and exercise, hormone changes throughout the menstrual cycle can cause a woman’s metabolism to prioritize the burning of fat over carbohydrate in the last two weeks and may be an optimal time to use slow, steady state training.

Planning training programs for men, however, could prove simpler as they're not subject to such changes in metabolism. So, for men, higher intensity workouts may well be the answer for burning more calories.

HIIT training is also much more time efficient, with most HIIT training taking one-third the time of common steady-state exercises. So, people who find it hard to get time for a workout may have no choice but to use a HIIT routine.

So, while lower intensity training may be more beneficial to women, varying training and planning a program to time your type of cardio to the most appropriate time are always significant factors to being successful in attaining the goals in mind.

Whereas for recreational exercisers, sometimes preference has a bigger impact on which exercise is done. After all, the best training program is useless, if it isn't carried out. 

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In choosing exercises to carry out during cardio, it should also be mentioned that running, either on the road or the treadmill, has a greater injury risk to both connective tissue, like tendons and ligaments, and to the joints themselves, than alternatives like cycling or running on elliptical machine or using the rowing machine. So, keeping impact low during steady-state activities can help prevent aches, pains and injuries and allow more time to be put in the gym.

It's also worth considering that using resistance exercises during HIIT training can help preserve muscle mass better than non-weighted exercises like aerobics or bike sprints, while still helping to improve fitness and cardiovascular health. With this in mind, weight training circuits could be the best choice when looking for the most efficient cardio routine.