Keep Jogging Or Rest?

Picture by Richard Seow

For those of you old enough to remember former Singapore runner, Syed Ahmad Taha - he's the last Singaporean runner to run the 10,00m on the track in under 33 mins before Soh Rui Yong in 2012, and Melvin Wong in 2015 at the Singapore SEA Games. Syed ran the 10,000m in 32:41 min in 1990.

I remember watching him do interval training (the original HIIT) at the old National Stadium back in 1988. When I was a teenage runner, those intervals we did certainly did not have such a fancy name like HIIT. You run 15 intervals or repetitions of 400m with a one minute rest in between or the coach will say run 6 x 1km going every 5 minutes (meaning if you run your kilometer in 3:50 min, you get 1:10 min rest before starting again).

Syed Ahmad Taha was doing 25 x 400m with a 60 seconds rest and he would be lying on the track recovering while you could see his heart thumping away. He would spring back up as his coach told him to get ready for the next rep. No super shoes, no super spikes back then in 1990. Respect!

A quick question for all runners before reading the rest of this article. During your track intervals training, do you normally continue to jog/ run after the interval or just rest before starting the next rep?

Well, no prizes for guessing that this post compares active recovery (jog/ run) versus passive recovery (lying down or slow walk) between repeats during interval training.

The study had well trained runners do 4x 2:00 minute at their maximum aerobic speed at an outdoor track, with a 2 minute rest or 2 minute jogging between the intervals.

Resting (rather than jogging during the rest period) enabled the runners to work harder and spend more time at peak VO2. This is the whole point of interval training, to spend more time running in the 90-100 percent VO2 max region. The rest allowed the runners to suffer more. Perceived effort by the runners after each run was also lower with rest in between. The researchers concluded that complete rest is preferable for this type of workout. 

Some points to note. The runs were done at identical running speed. The runners may be able to run faster if they were allowed to run the interval at their own pace with a jog recovery since jogging (low intensity exercise) keeps the blood flowing, which eliminates lactic acid quicker to enable you to go faster at the next rep).

Lactate (or lactic acid) levels were only measured after the workout was over, lactate levels were significantly higher (6.93 vs 6.24 mmol/ L) while the runners rested. 

The question I'm pondering on is whether to make your workout harder or easier? Is standing still to rest better since your muscles are filled with lactic acid and you get to practice running in that state? 

Or is jogging better since you can train your body to eliminate lactic acid quicker form your bloodsteam and thus enabling you to run faster. Perhaps, you can do complete rest while training for your next race this year and do the jogging rest for the same race next year and see which gives a better race timing. Definitely a good study topic for researchers.

If your goal is to run each rep as quickly as possible, then you are better off resting or just walking a little, if the recovery time is a minute or under since resting helps to restore phosphocreatine, which fuels your sprints and the starting stages of your longer runs. (This is why some athletes that require frequent sprints in the sport - hockey, basketball, football etc take creatine) which can be a separate post.

However if your rest period is 2 minutes or longer, light jogging may possibly help you run faster since you are actively clearing lactic acid and other metabolites.

Reference 

Sanchez-Otero T, Tumil JL, Boullosa D et al (2022). Acive Versus Passive Recovery During An Aerobic Interval Training Session In Well-trained Runners. Euro J Appl Physiol. 122(5): 1281-1291. DOI: 10.1007/s00421-022-04926-2.

Isometric Exercise Training Trumps HIIT

Isometric glutes and quads training

An article in the Straits Times last year showed that an increasing number of Singaporeans have hypertension or high blood pressure. 

This is not just in Singapore, hypertension is a global health problem that is largely treated by anti-hypertensive medication. However, even though anti-hypertensive medication is mostly effective, other than being costly over the long term, it has adverse side effects and also poor adherence rates. My own grandmother used to take one pill a day, then she reduced the dose to half herself before stopping altogether.

Traditionally, moderate intensity aerobic exercise is currently recognised as the recommended modality for managing blood pressure problems. Current exercise compliance to benefit long term cardiovascular risk is also poor. Hence, a different approach may be needed to manage hypertension.

The paper referenced below investigated the effects of isometric exercises versus high intensity interval training (HIIT) to find out which is more effective at reducing resting and ambulatory blood pressure (BP).

Both IET and HIIT were found to be effective, however IET was significantly more effective at reducing resting BP compared to HIIT. Systolic and diastolic BP were reduced by 8.50 mmHG and 4.07mmHG after IET versus 2.86 mmHG and 2.48 mmHG following HIIT.

HIIT lessened the resting heart rate significantly by 3.17 beats per minute (bpm) versus 1.34 bpm for IET. 

Duration of exercise, subject's medication status and time of diagnosis of hypertension had no effect on the results.

Compared to HIIT, IET had superior results in the management of resting BP with reductions similar to or greater than anti-hypertensive medication. HIIT was still found to be highly effective at reducing resting BP and may have wider physiological benefits than IET since it was more effective at reducing resting heart rate. 

Teaching patients to use IET to reduce hypertension should definitely be considered. Most of the studies that studied IET used hand grip exercises for the upper limb and stationary wall squats or leg extension for the lower limb. Cycling intervals were the most common for HIIT studies.

The authors concluded that getting patients with hypertension to do IET for controlling their blood pressure should be considered, while HIIT better for maintenance of good health.

Now you know IET trumps HIIT when it comes to lowering blood pressure.

Reference

Edwards J,  De Caux A, Donaldson Jet al (20). Isometric Exercise Versus High-Intensity Interval training For The Management Of Blood Pressure: A Systematic Review And Meta-Analysis. BJSM. DOI: 0.1136/bjsports-2021-10442.

*Thanks to Megan for getting me the article

Instead Of Complaining About Wearing Face Masks..

He wore a mask, I didn't - posed lah ;) 

Almost daily during the circuit breaker (CB) period last year, my older boy and I went out to ride our bikes since there were hardly any cars on the road.  Most of the time we had our cloth face masks on. Needless to say, we found riding uphill more difficult when having them on. 

Made it to the top of Mt. Faber

Newly published research backs this up. Researchers had 28 young (18 to 29 years) and healthy participants perform 2 maximal exercise tests on a treadmill. One with and one without a cloth face mask.

Each participant runs to complete exhaustion as the treadmill speed and incline is increased every 3 minutes and the time to exhaustion is recorded. This is used to estimate VO2 max levels. Heart rate, blood pressure, rate of perceived exertion and the participant's perceptions of wearing a face mask while running were also recorded.

Key findings were that cloth face masks reduced run time to exhaustion by 14 percent and VO2 max by 29 percent. With masks on, the participants felt more short of breath and claustrophobic at higher exercise intensities compared to not wearing masks. Blood oxygenation levels (Sp O2 levels) were also lower when cloth face masks were worn. The reduced levels of oxygen in the blood show a definite physiological effect. 

The more effective the mask in filtration capacity (the more protection for the wearer), the more it will affect exercise performance. Take home message is that using a mask during exercise does make it a lot harder. The researchers recommend that exercise time, frequency and especially intensity be modified when wearing a cloth face mask.

The researchers also cautioned that their findings of impaired performance with cloth face masks may be in part due to the perceived discomfort. Meaning, the participants were less motivated to keep running at higher treadmill speed and incline. 

My racing days are long gone, but if I were still training and competing, I'll probably don a cloth face mask while training (sometimes) to up the intensity a few notches so that when I race without a cloth face mask, I'll be hard to beat. That's just like respiratory muscle training. But that is just me. Please do not take this as training advice! 

Reference

Driver S, Reynolds M, Brown K et al (2021). Effects Of Wearing A Cloth Face Mask On Performance, Physiological And Perceptual Responses During a Graded Treadmill Running Exercise Test. BJSM. epub first 13 April 2021. DOI: 10.1136/bjsports-2020-103758.

Overdoing HIIT Sessions Can Affect Your Health

Picture from The Pit. HIIT or just *circuit training?

Many of my *patients tell me they are doing HIIT classes now. If you interested about your fitness and have been exercising regularly, you will definitely know what HIIT stands for. High intensity, interval training.

When I was a teenage runner, those intervals we did certainly did not have such a fancy name like HIIT. You run 15 intervals or repetitions of 400m with a one minute rest in between or the coach will say run 6 x 1km going every 5 minutes (meaning if you run your kilometer in 3:50 min, you get 1:10 min rest before starting again).

I've written how HIIT can be beneficial and how it can even reduce growth in cancer cells. Since HIIT is a super time efficient method for improving aerobic fitness and other health outcomes and metabolic conditions such as diabetes, high cholesterol or high blood pressure. 

One such outcome is increasing our cell mitochondria (power generators in our cells) in our muscles. With more mitochondria in our cells, we become stronger. 

Before you think more HIIT is better, a recent small study showed that people who tried to do 5 HIIT sessions in a week ended up with sudden and severe declines in their mitochondria function, along with blood sugar dysfunction. 

When the subjects decreased their HIIT sessions, their metabolic condition started to improve but did not disappear, hinting that the benefits of extremely strenuous exercise may still depend on how much we do and how we allow ourselves to rest and recover.

The researchers first tested the subjects in their lab for the current fitness levels and metabolic health, which included blood sugar levels throughout the day. In the first week, 2 sessions of HIIT were performed, 5 reps of 4 minute long bike intervals on a stationary bike with 3 mins rest in between. The subjects pedaled as hard as they could while their power output was tracked. Their leg muscles were biopsied while a 24 hour blood sugar control was investigated.

In week 2, they did 3HIIT sessions while increasing some of their intervals to 8 minutes. During week 3, they did 5 HIIT sessions with a mix of 4 and 8 minute intervals of all out cycling. Week 4 allowed for some recovery and they subjects and the amount and intensity of exercises were halved. All the tests were repeated weekly.

The findings showed the subjects getting stronger by week 2. They were pedaling harder and getting fitter, better daily blood sugar control and more mitochondria in the cells. These mitochondria were also more efficient, producing greater energy compared to baseline.

However, by week 3, the subjects were not able to generate more power, their muscle biopsies showed that their mitochondria were only producing 60 percent of the energy of week 2. Blood sugar control levels were spiking and dipping throughout the day.

After allowing for recovery in week 4, the following week showed the mitochondria producing more energy, but still 25 percent less than week 2. Blood sugar levels stabilized too, but again not to the same extent as week 2. The subjects could however ride with the same or even greater vigor as with week 2.

The researchers did not find out what exactly caused the decline in results (glucose intolerance and insulin secretion)  that occurred after week 3. It may be the combination of total biochemical changes that weakened the mitochondria which in turn disrupted the blood sugar control levels. 

This study was done on normal healthy subjects and not athletes nor people with metabolic conditions such as diabetes, high cholesterol or high blood pressure. The latter group attempting such training must get the go ahead from your medical professional. For those of us who just want to be healthier, don't do HIIT sessions excessively since previous studies and formal recommendations suggest 3 intense sessions in a week as maximum. Otherwise, injuries may come knocking on your doors too. 

The researchers managed to assess blood glucose profiles in world class endurance athletes and found that they, too had impaired glucose control when compared with a matched control group. So for athletes who want to be stronger, faster quicker, do allow ample time for recovery between training sessions.

Reference

Flockhart M, Nilsson LC, Tais S et al (2021). Excessive Exercise Training Causes Mitochondrial Functional Impairment And Decreases Glucose Tolerance In Healthy Volunteers. Cell Metab. DOI: 10.1016/jcmet.2021.02.017

*Most of these 'HIIT' sessions my patients go to are in fact just fancy names for circuit training. You have say 8 stations where you do sit ups, jumping jacks, box jumps etc for 30 secs, rest and move on to the next station. One can do 2-4 'circuits' of these 8 stations. I guess going to a HIIT session sounds nicer than going for circuit training. That's probably how gyms sell these classes.

The research describes HIIT training as run 15 intervals or repetitions of 400m with a one minute rest in between or perhaps run 6 x 1km going every 5 minutes (meaning if you run your kilometer in 3:50 min, you get 1:10 min rest before starting again). Or you could be cyling 4 mins at a certain intensity/ wattage and repeat that 4-8 times. 

High Intensity Interval Training (HIIT) Reduces Cancer Cell Growth?

Picture by richseow from Flickr

I've written positively before about the effects of running on cancer a few years ago. Now there seems to be more evidence that even a single session of high intensity interval training (HIIT) may significantly slow the growth of colon cancer cells.

Researchers had male colorectal cancer survivors perform either a single HIIT session or do HIIT regularly for a month.

After a ten minute warm up, the single HIIT group did four intervals of four minutes cycling (at 85to 95 percent maximum heart rate) with three minutes of recovery in between. The other group did this same session three times a week for a month.

Picture by jungle jim3 from Flickr

Blood samples were taken from these subjects before and after the HIIT sessions. Blood samples before exercise had no effect whatsoever on the cancer cells. Blood samples after the HIIT sessions showed a decrease in the cancer cells immediately.

While comparing the single session HIIT group with the other, there was no significant difference in the blood samples.

During high intensity exercises, our muscles releases lots of myokines (inflammatory cytokines) compared to moderate intensity exercises.

The researchers attributed the cancer cells reduction to cytokines (or inflammatory markers) found in the bloodstream after exercise.

The researchers suggested that the reduction in cancer cells in the colon is not specific to those who had cancer before. Other studies have found similar reductions in prostate cancer cells in healthy individuals as well.

Every individual tolerates and responds differently to exercises, especially HIIT sessions. Train don't strain is important too.



Reference

Devin JL, Hill MM et al (2019). Acute High Intensity Interval Exercise Reduces Colon Cancer Cell Growth. J Physiol. DOI: 10.1113/JP277648.

Aerobic Exercises Key To Aging Well?

Me on the left. Picture by Jeffrey Keng from Cycleworx

Slightly more than a year ago, I wrote that strength training may be just as important (if not more) than aerobic exercises. Why? Strength training has been found to decrease rates of early and cancer related death.

And earlier this year I disagreed with a funded study by Les Mills International when the article suggested that lifting weights was more beneficial for losing weight compared to running or cycling (aerobic exercises).

Now, some new research seems to show that aerobic exercises (like running, cycling, rowing or swimming) can make our cells younger. That same study found that weight training may not cause the same physiological changes in our cells.

Way back in 2009, a study found that competitive middle-aged runners had extended telomeres compared to inactive people of the same age. What are telomeres? All of us have telomeres at the tips of our chromosomes. Telomeres help protect our cells from damage and have been found to shorten and fray as a cell ages.

Many of the researchers in that 2009 study came together for this recent study to investigate whether exercise would change our telomeres.  They also wanted to know what type of exercise were needed and whether intensity played a part. It is hypothesized by the scientists that exercise helps lengthen the telomeres.

The researchers recruited a group of healthy middle aged men and women who did not exercise. They were tested for  their aerobic fitness and telomere length. In addition, blood markers of telomerase (an enzyme that influences telomere length) were tested as well.

Some in this group were randomly assigned to continue with their lives as normal as a control group. They did no exercises.

Others started a supervised program of brisk walking or running for 45 minutes three times a week or a high intensity interval program of four minutes of strenuous exercise followed by four minute rests with this repeated four times.

A third group took up weight training, doing a circuit of resistance exercises three times a week.

Heart rates were monitored and the exercise program was carried out for six months. Results were tested after this and all the subjects who exercised were found to be more aerobically fit.

At molecular level however, there were differences. Those who did the aerobic exercises and interval training had much longer telomeres than before starting the exercise program and more telomerase activity.

Those who weight trained and those in the control group (who did not exercise) had no change in telomere length. Some even had shortened telomere lengths.

Those who did weight training produced less nitric oxide, which is thought to affect telomerse activity and contribute to lengthening telomeres.

Even though weight training was strenuous, overall heart rate was lower compared to running in the study. This results in less blood flow and probably less physiological response from the blood vessels.

The researchers suggested that exercise needs to be aerobically taxing to extend telomere length and slow cellular level aging. In this aspect, endurance exercise was clearly ahead of resistance training.

The findings do not indicate that weight training does not combat aging as it also helped improved fitness, which itself is a very important indicator of longevity.

Like I wrote before, current research shows that both strength training and aerobic exercises are necessary to be healthy and functional. So run, bike or lift weights, (or whatever exercise you prefer) as they are all beneficial, it's much more important to keep moving.

I wanna for live a long time, so I lift weights too

References

Werner CM, Furster T et al (2009). Physical Exercise Prevents Cellular Senescence In Circulating Leococytes And In The Vessel Wall. Circulation. 120 (24): 2438-2437. DOI: 10.1161/CirculationHA.109.861005.

Werner CM, Hecksteden A (2018). Differential Effects Of Endurance, Interval And Resistance Training On Telomerase Activity And Telomere Length In A Randomized Controlled Trial. Euro Heart J. ehy585. https://doi.org/10.1093/eurheatj/ehy585.