Blogs & News

You get the email alert and what do you know, it’s that time of year again- health assessment time. You’re probably thinking, how did that sneak up again so quickly? And has it really been a year since I promised myself I would make some lifestyle changes, especially after the disaster COVID rolled out.

Why is fitness important from a health perspective?

Data from research suggests that there is a predictive correlation between poor fitness (V02_max), cardiovascular events and all-cause mortality (Blair, 1996; Kessler, Sisson & Short, 2012). Unfit individuals had in some cases more than 3 times the risk of mortality across all levels of body composition (BMI). Those who were overweight or obese but recorded good fitness scores in some cases had higher projected life compared to individuals who were not overweight and unfit (Barry, Caputo & Kang, 2018; Blair et al, 1996; Blair, 1996; Ritchie & Roser, 2021)

(Blair, 1996)

(World Health Organisation, 2021)

Results from maximal fitness testing and the medical assessments of 32,421 men and women in the following study indicate that those who recorded lower fitness scores were at higher risk of cardiovascular events and other health complications over those who were considered “moderately or highly fit” with secondary risk factors such as being a smoker or having high cholesterol (Swain & Franklin, 2006; Blair et al, 1996). With the research highlighting the importance on fitness and its effects on cardiovascular health and mortality it is important to also link in the correlation between hypertension, high cholesterol and diabetes and obesity.

With so many people these days worried about “weight loss” they miss the real importance of a healthy body composition and what that should look like. Your body composition is made up of muscle, bone, water and fat. This is why you shouldn’t always focus on the numbers your scales give you. Your scales can tell you that you have lost weight but in actual fact have you lost muscle mass and gained fat mass? I think it is important to start looking at changes in body composition as “fat loss” rather than “weight loss” as a change in weight may not produce positive effects on shape, muscle health and fat mass. I will refer to these changes further down as “fat loss”. In the meantime, understanding your metabolic health is also important and you can do so here.

One of the biggest fitness boom words in the last couple of years is HIIT training- aka high intensity interval training. Promoted by all the big fitness personalities and Instagram models as the most effective tool for weight loss. What really is more important weight loss or health? Are they the same? Let’s see what the research says about some of the different forms of cardio training.

What is HIIT?

Training that elicits 85-95% maximum heart rate in a normal population. HIIT training originally came from SIT training (sprint interval training) which was largely seen in elite athletes working at over 100% of V02max to enhance performance.

What is steady state?

Also known as MICT (moderate intensity continuous training) is said just as the name suggests! A moderate intensity bout of training!

What some more of the science has to say:

A study by Foster et al (2015) looked into the effects of high intensity interval training vs steady state training on fitness (aerobic and anaerobic capacity). They used 55 untrained college students and performed 24 training sessions for 3 groups over 8 weeks. They compared HIIT Tabata (20 rounds of 8s on/ 10s rest), steady state cardio (20min total) and a Meyer protocol (13 rounds of 30s on/ 60s recovery). The results suggest that all 3 groups showed an increase in fitness (V02_max), peak and mean power output. Although out of all three groups it was reported that the Tabata protocol was the least enjoyable to adhere to but was the most time efficient.

Another study, Zhang et al (2020) looked at different exercise protocols and fat loss. They used 4 groups: Sprint interval training- SIT (6s all out/ 9s passive recovery), Supramaximal SIT¹²⁰ (60s over maximal threshold/ 90s passive recovery), Moderate intensity continuous training- MICT (steady state at 60% of maximal) & High intensity interval training- HIIT (4mins on/ 3mins passive recovery). The results from this study indicate that:
*There were similar reductions in whole body and regional fat mass in all groups.

*SIT, SIT¹²⁰ & HIIT produced a greater decrease in visceral fat mass (in the abdominal cavity and around the vital organs) than the MICT group. This was said to be as a result in an increase post-exercise energy expenditure. 

The “LifeSprints” study by Boucher in 2011 suggests that in the lower intensity steady state cardio trials, not enough levels of epinephrine (adrenaline) were present to stimulate fat breakdown in the muscle cells. During and after higher intensity exercise epinephrine and norepinephrine floats around in the system which stimulates “hormone sensitive lipase” to start breaking down fat in the fat cells. Therefore, the presence of epinephrine could be considered a major lipoliptic factor in fat breakdown (Trapp, Chisholm & Boutcher, 2007). During higher intensity exercise reaching maximal levels, not only does the body switch to carbohydrate as a main source of energy, a by-product of the anaerobic system (as seen in maximal intensities) is lactic acid. Lactic acid is said to be a blocker of epinephrine. Can you see where I am going with this? The results shown through LifeSprints indicated three times as much body fat was reduced in about half the exercise at an intensity equivalent to 60% of peak oxygen uptake/ maximal effort.

So which one is actually best?
It depends on your goal! For general health and fitness I recommend a good mixture of both! To put it simply both forms of exercise will get you fitter and help you to fat mass although interval training can be more time efficient than steady state, drumroll… if done properly. Harder doesn’t necessarily mean better. These days with all the research available you are more than likely to find evidence to support most arguments you have as science is continually evolving.

Interval training isn’t as simple as banging together a workout that reflects something like 30s intense exercise and 30s recovery. There is some strong evidence to suggest those that have mastered it have brought it down to the “perfect combination”. How you structure this will largely depend on your fat loss outcome/ metabolic response (Trapp et al, 2007; Christmass, Dawson, & Arthur, 1999; Essén, B & Kaijser, 1978; McGarvey, Jones & Petersen, 2005). As you can see from the research volume (length of sprint), recovery (length of rest period), duration (total workout time) and frequency were all important factors.

You’re probably reading the results from these studies and thinking so what is it that I should be doing? Here are some of the take homes:

• SOMETHING is always better than nothing. The Australian Guidelines ask for 150mins of moderate intensity exercise or 75 vigorous to be considered “physically active”. They also state that the recommendation is 210mins of moderate intensity exercise per week for weight loss. If you’re currently inactive, start with some brisk walking. You can add intensity with a change of pace, some stairs, hills or sand.

• Eating well is key. Did you know, one Tim Tam is equivalent to 3.4km of walking at a pace of 5km/h (which would equate to 41 minutes) on the treadmill?! Other variables to speed up the rate at which the 1 Tim Tam would be burnt would be of course the intensity of your exercise and other physiological variables such as the amount of oxygen your body is able to utilise efficiently (in this example the subject was measured to be 0.75L.min) which would also depend on some things like your size and aerobic capacity (good aerobic fitness levels will indicate a higher aerobic capacity). This is a great way to understand how important diet is when trying to lose weight. You can't out train a bad diet. Therefore, a good diet is imperative when trying to lose weight and even more beneficial when paired with the a correct training regime.

• Try a mixture of modalities. This is to avoid boredom and training monotony which is a large risk factor for injury. Load is key. Too much load and/ or intensity too quickly or sustained over a period of time is a quick way to finding yourself injured. Some days should be lower intensity with slightly more volume and other days shorter sessions at higher intensity. Also try to include some form of resistance training, especially as you get older to help maintain or improve your muscle mass.

• High intensity will likely get you fitter faster providing you are actually working at a high intensity. Are you really pushing yourself at the pace you need to be at to justify the short bouts of work you are doing? Is your body ready or equipped to handle such intensity?

• Have a plan. Write your weekly workout plans down. Give yourself a day and time to keep yourself accountable. Writing down your workouts or what you will do will also take the “thinking” out of it.

• What works for you might not work for me. Training, like diet is very individual. Use some of the protocols mentioned above from the research and give yourself 4-8 weeks paired with good nutrition and see how you go.

• Invest in some professional help such as a qualified Exercise Physiologist.

• Most importantly- BE CONSISTENT. You could have the most bullet proof training regime known to man though if you aren’t consistent you are just treading water.

• If you have not exercised previously or for a long time, having a medical review prior to attempting high intensity training is recommended.

References

Achten, J., Gleeson, M., & Jeukendrup, A. (2002). Determination of the exercise intensity that elicits maximal fat oxidation. Medicine & Science In Sports & Exercise, 34(1), 92-97. doi: 10.1097/00005768-200201000-00015

Barry, V. W., Caputo, J. L., & Kang, M. (2018). The joint association of fitness and fatness on cardiovascular disease mortality: a meta-analysis. Progress in cardiovascular diseases, 61(2), 136-141.

Blair, S. (1996). Influences of Cardiorespiratory Fitness and Other Precursors on Cardiovascular Disease and All-Cause Mortality in Men and Women. JAMA: The Journal Of The American Medical Association, 276(3), 205. doi: 10.1001/jama.1996.03540030039029

Blair, S. N., Kampert, J. B., Kohl, H. W., Barlow, C. E., Macera, C. A., Paffenbarger, R. S., & Gibbons, L. W. (1996). Influences of cardiorespiratory fitness and other precursors on cardiovascular disease and all-cause mortality in men and women. Jama, 276(3), 205-210.

Boutcher, S. (2011). High-Intensity Intermittent Exercise and Fat Loss. Journal Of Obesity, 2011, 1-10. doi: 10.1155/2011/868305

Christmass, M., Dawson, B., & Arthur, P. (1999). Effect of work and recovery duration on skeletal muscle oxygenation and fuel use during sustained intermittent exercise. European Journal Of Applied Physiology And Occupational Physiology, 80(5), 436-447. doi: 10.1007/s004210050615

Essén, B., & Kaijser, L. (1978). Regulation of glycolysis in intermittent exercise in man. The Journal Of Physiology, 281(1), 499-511. doi: 10.1113/jphysiol.1978.sp012436

Foster, C., Farland, C. V., Guidotti, F., Harbin, M., Roberts, B., Schuette, J., ... & Porcari, J. P. (2015). The effects of high intensity interval training vs steady state training on aerobic and anaerobic capacity. Journal of sports science & medicine, 14(4), 747.

Hurley, B., Nemeth, P., Martin, W., Hagberg, J., Dalsky, G., & Holloszy, J. (1986). Muscle triglyceride utilization during exercise: effect of training. Journal Of Applied Physiology, 60(2), 562-567. doi: 10.1152/jappl.1986.60.2.562

Keating, S., Machan, E., O'Connor, H., Gerofi, J., Sainsbury, A., Caterson, I., & Johnson, N. (2014). Continuous Exercise but Not High Intensity Interval Training Improves Fat Distribution in Overweight Adults. Journal Of Obesity, 2014, 1-12. doi: 10.1155/2014/834865

Kessler, H., Sisson, S., & Short, K. (2012). The Potential for High-Intensity Interval Training to Reduce Cardiometabolic Disease Risk. Sports Medicine, 42(6), 489-509. doi: 10.2165/11630910-000000000-00000

Martins, C., Kazakova, I., Ludviksen, M., Mehus, I., Wisloff, U., & Kulseng, B. et al. (2016). High-Intensity Interval Training and Isocaloric Moderate-Intensity Continuous Training Result in Similar Improvements in Body Composition and Fitness in Obese Individuals. International Journal Of Sport Nutrition And Exercise Metabolism, 26(3), 197-204. doi: 10.1123/ijsnem.2015-0078

McGarvey, W., Jones, R., & Petersen, S. (2005). Excess Post-Exercise Oxygen Consumption Following Continuous and Interval Cycling Exercise. International Journal Of Sport Nutrition And Exercise Metabolism, 15(1), 28-37. doi: 10.1123/ijsnem.15.1.28

Ritchie, H., & Roser, M. (2021). Causes of Death. Retrieved 5 July 2021, from https://ourworldindata.org/causes-of-death

Swain, D., & Franklin, B. (2006). Comparison of Cardioprotective Benefits of Vigorous Versus Moderate Intensity Aerobic Exercise. The American Journal Of Cardiology, 97(1), 141-147. doi: 10.1016/j.amjcard.2005.07.130

Trapp, E., Chisholm, D., & Boutcher, S. (2007). Metabolic response of trained and untrained women during high-intensity intermittent cycle exercise. American Journal Of Physiology-Regulatory, Integrative And Comparative Physiology, 293(6), R2370-R2375. doi: 10.1152/ajpregu.00780.2006