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Training Log : Week 5 - Day 30-34 Immune system

Posted Jul 03 2009 3:44pm
Day 30 - 34 Mon - Fri

All training have been on a standstill as I need to summon all my energy to combat this cold and carry on everyday activities. There is a fear that the cold will prolong if I put myself under more strain, which brought me thinking about our .

The estimated one trillion cells of our immune system is supposed to help keep us free from invading organisms such as bacteria and viruses that may cause diseases.
  • Does exercise strengthen our immune system & help us stay healthy?


  • Does exercise give our immune system additional stressors and make us susceptible to invading virus & bacteria?

that impair our immune system's functions and increase our risk of catching colds:

  • old age
  • cigarette smoking
  • stress - physical & psychological - both produces stress hormones, cortisol & adrenalin
  • poor nutrition - too much or too little of 'good' & 'bad' foods
  • fatigue and lack of sleep - over-worked
  • over-training

With the exception of cigarette smoking, I admit that I have all the factors (in varying degrees). However, we should also consider these other factors:

  • - In Malaysia, the common cold is most common. It usually peaks when the weather changes hot & hazy to cold & rainy.
  • - over-consumption of a seasonal fruits such as durians, rambutans & longan usually raises the body temperature and makes us 'heaty' & susceptible to fever & headaches. I guess overworking the stomach is additional stressor. When the durian season comes, there is a celebratory air where people of all walks of life (rich, poor, smartly dressed, simple 'Joe') gather to open the hard, thorny skin & eat under shady trees, hold durian eating parties at home & at orchards. Old wives wisdom recommends eating durian (heaty) and mangosteen (cooling) together to contra off the effects.
  • - is on the increase. Those who drive cars do not realise it, but if you walk on the road, you'd be appalled by the amount of infected mucus & spit. Yes, when you have a cold, you have phlegm which have to be removed by spitting it out. Do it properly (in the sink or into a tissue & disposed off). In my teens, I remember a much cleaner environment. People cared about others. They do not want to infect others & took pains to hold their spit & dispose of it in safely. Nowadays, with this new self-centeredness, people will do whatever it takes to rid themselves of the phlegm whenever & wherever they can in public. Sneezing without a hankie or tissue, sending infected droplets airborne or onto their hands & fingers and then they continue to go about touching everything (urgh!!) - what's more appalling is that they (the upper/middle or lower crust of society) never realise it & will never admit it. I did tick off a few people, but they just up-their noses & walked away. Now, Dettol is raking in big bucks selling disinfectants (which end up polluting the water ways but people still use it to keep only themselves germ-free). Thus, by being , these irresponsible people have created a disease-filled environment for themselves & the society at large!

Back to the question of the -

I guess one should always take the 'middle-path' - ie,

  • , consistent exercise will our immune system such that we rarely catch a cold. It temporarily boost the production of macrophages (cells that attack bacteria), immune cells circulate through the body more quickly and are better able to kill bacteria and viruses. After exercise ends, the immune system generally returns to normal within a few hours, but consistent, regular exercise seems to make these changes a bit more long-lasting
  • Too much exercising can, on the other hand, our immunity. Research shows that more than 90 minutes of high-intensity endurance exercise can make athletes susceptible to illness for up to 72 hours after the exercise session. The body produces cortisol and adrenaline (stress hormones) that raise blood pressure, cholesterol levels and suppress the immune system. This effect has been linked to the increased susceptibility to infection in endurance athletes after extreme exercise (such as marathon running or Ironman-distance triathlon training).

Final word from Elizabeth Quinn, :

"If you are already ill, you should be careful about exercising too intensely. Your immune system is already taxed by fighting your infection, and additional stress could undermine your recovery. In general, if you have mild cold symptoms and no fever, light or moderate exercise may help you feel a bit better and actually boost your immune system. Intense exercise will only make things worse and likely extend your illness. "

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