You've heard it before – adversity breeds character. For us to improve and grow, both physically and mentally, we need to push ourselves beyond what we thought was possible. It's only our false beliefs that stop us achieving what we want.
We need to stress our physical bodies so they regenerate and improve themselves; otherwise the body's systems weaken and break down. Use it or lose it! After periods of short term stress such as exercise or a challenging task, the body initiates a cascade of hormonal responses to repair and upgrade itself. Hormones that increase health and fitness in all systems are up-regulated, while those that degrade the body are down-regulated. Chemicals that make us feel good are released, and even the brain and nervous system benefit via neurogenesis. (more detailed information on these changes is available here)
Of course these acute stressors are different from chronic stressors. While a short term stressor results in multiple positive genetic expressions in the body, chronic or long-term stressors drain the body of its resources as it never gets a chance to rest and repair.
There are many different ways to apply a healthy stress to the physical body, and some you might not have thought of. They all provide a mental stress - be it a resistance to the challenge, or the false belief that you just can't do it. Push through this resistance and find your true strength.
Slow steady state exercise such as jogging or swimming. As this is utilising the body's slow-burning oxygen based energy system (called the aerobic system), all systems that contribute to this energy production are up-regulated. The body also upgrades itself to become more efficient with a higher capacity cardiovascular system, stronger muscles and connective tissue, and increased bone density. Feel good chemicals are released, cognition is improved and neurogenesis occurs. The effects of aging are slowed, and some diseases such as diabetes and depression can be reversed.
Short bursts of explosive exercise such as lifting heavy weights, sprinting, jumping or martial arts. These produce the same benefits as aerobic exercise, but with a focus on strength, power and metabolic increases, rather than endurance and overall cardiovascular health. Anaerobic exercise increases testosterone and growth hormone well beyond any other method, short of hormonal replacement or steroids.
Ice baths, cyrotherapy, or even a cold shower. The cold triggers a metabolic response in the body to keep its core temperature warm, and readies the body for action, releasing adrenalin and norepinephrine. This metabolic response also increases the number of cell mitochondria, meaning more energy production and better cold tolerance. It triggers the activation of anti-inflammatory and anti-oxidant pathways. It increases the body's production of collagen, so it's good for arthritic pain, as well as skin and tendons.
A sauna, sweat lodge or hot yoga. The body literally sweats out toxins in these environments. The heat relaxes your body and muscles, while the stress on the body confers anti-inflammatory effects. It also improves the cardiovascular system and increases the body's ability to lower its core temperature when required.
Short term fasting (not eating for 12 hours) puts the body into "clean-up mode". As no energy is coming in to process, it turns its attention to reclaiming energy and resources from damaged cells in the body – a process called autophagy. It has anti-inflammatory and anti-oxidative effects, while improving fat burning and insulin sensitivity. Longer (24-48 hour) fasts have additional benefits, and have been used to effectively treat some diseases. While longer fasts still confer the above benefits, fasting for over 72 hours will start to heavily stress the body and is not recommended without medical advice. This is different from a juice fast which can also be very beneficial due to caloric restriction, conferring many of the same benefits.
The pain of a cut, a stretch or deep tissue massage mobilises the body's healing agents, protecting and regenerating tissue, increasing immune response activity and yielding anti-inflammatory effects. The ability to breathe through the pain oxygenates the blood to promote faster healing, and also releases endorphins.