Figure 3.2 Captain of Stress Stress hormones whip one another into a frenzy when you have to fight or flee. As captains of the stress team, cortisol soothes your response (by turning off your immune system), and epinephrine gets your blood moving (sometimes too quickly). You survive to live another day, but at a price.

      So what role does our Major Ager of stem cell slowdown play in all of this? Well, the stem cells’ regenerative properties are crucial here because of the damage that our environment and the resultant stress can do. Stress is all about adapting to the challenges of life. It is not the strongest or the fastest who wins the game of life, but the most adaptable. When stress hormones damage tissues, cells and organs in the ways we talked about above, stem cells replace damaged cells and make the repairs. It’s one of the reasons why we can’t constantly be mentally revved; we need to idle our brains to allow the stem cells to do their job and replenish those cells and tissues that have been battered by bosses, bullies or brats. So when a toxic food has shrivelled our liver, or having a baby has reduced our heart function, or we have damaged an artery by overreacting to a sloppy coiffeur, stem cells come to the rescue to rebuild us as good as we were before. To boot, stress shortens those telomeres and turns down telomerase, so that the fastest-producing cells – stem cells – have the most difficulty keeping up.

      Even five years ago, we didn’t know this stem cell replenishment was true for most organs, but now we know that every organ seems to recruit backup stem cells from the bone marrow to resuscitate itself. These emergency relief worker cells lay the groundwork for re-creating our organs.

      Stress has a cascading effect on many aspects of our health. It increases the risk of arterial ageing, it damages our immune system, and it also makes us prime candidates for life-altering (or life-ending) accidents – many accident victims admit to having been stressed and angry before the mishap – not to mention affecting our mental health. Stress also releases steroids, which, when given in higher prescription doses, are a legally defensible reason for a rage response. Stress isn’t just something you write off as a need for spa treatments; it’s a major biological driver of ageing.

      Now, your response to stress is somewhat hereditary. We all have differences in our genes that control the HPA axis, meaning that some of us never have a strong response to a threat, while others have a full-fledged response to even a minor threat. (Sound like anyone you know?) But that hereditary predisposition can be altered at any time by extreme stresses. With major stresses early in life, your response becomes stronger, making you better able to handle future stresses. We see an example of this with our response to something called heat shock. When exposed to extreme heat, all animals, including humans, learn to adapt to the temperature so they can respond to it the next time they encounter it. It’s the biological basis of the mantra that what doesn’t kill us does indeed make us stronger. There are plenty of other techniques that can help minimize the internal damage caused by the pressures from the external world.

Your Belly: Stress Barometer

      When our ancestors faced periods of famine, they stored fat in their bellies with an organ called the omentum. We do the same thing: when we face chronic stress, we eat more food than we need, and we store it in our omentum for quick access to energy. The steroids released by the HPA axis are also sucked up by the omentum and help grow it as big as the muscles on a weight lifter who is dabbling in similar chemicals. That process proves to be damaging because the toxins from our omentum fat are pumped directly into surrounding organs. But it also offers a tangible way to gauge our stress levels: the bigger our bellies, the bigger our burden.

       YOU Tool: Anger Management

      It’s no secret that anger doesn’t help