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.

Cycling Causes Erectile Dysfunction And Male Infertility?

Helping hands to catch up

While runners often have to deal will claims that running will ruin their knees or wear them out, cyclists are often told that too much cycling can affect a man's fertility. Truth or myth?

Well, here's a study that should keep the naysayers quiet and let us cyclists keep riding. Researchers from University College London looked at 5282 male cyclists and grouped them into weekly cycling time of below 3.75 hours, 3.76-5.75 hours, 5.76- 8.5 hours and over 8.5 hours.

The authors found no link between cycling many miles a week (even for those  riding more than 8.5 hours), and infertility and erectile dysfunction.

Ventilation holes and to keep pressure of delicate areas

According to the authors, this may be partly attributed to better saddle technology (see picture above) which helps to "relieve pressure on nerves that prevent the uncomfortable 'numbness' that can occur when riding for a long time." 

However, cycling is linked to raised levels of PSA (or prostate specific antigen), which can signal prostate cancer. This is due to pressure from the saddle pressing on the prostate, mildly injuring it  causing inflammation and increasing PSA levels. So cyclists who spend lots of them on the saddle may end up getting unnecessary testing if a mildly raised PSA level is due to cycling and not prostate cancer. Again, before you get paranoid, the authors wrote that further research is necessary and the risk is only high in the most avid cyclists.


Reference

Hollingworth M, Harper A and Hamer M (2014). An Observational Study OF Erectile Dysfunction, Infertility, And Prostate Cancer In Regular Cyclists: Cycling For Health UK Study. J Men's Health. 11(2): 75-79. https://doi.org/10.1089/jomh.2014.0012.

Just in case you're wondering, I don't use any of those fancy "holey" saddles, even when I was riding 6 days a week before. Here's my saddle.