The following is an example of a 12-station HICT program. All exercises can be done with body weight and implements easily acquired in almost any setting (e.g., home, office, hotel room, etc.). The exercise order allows for a total body exercise to significantly increase the heart rate while the lower, upper, and core exercises function to maintain the increased heart rate while developing strength.

Exercises are performed for 30 seconds, with 10 seconds of transition time between bouts. Total time for the entire circuit workout is approximately 7 minutes. The circuit can be repeated 2 to 3 times.

1. Jumping jacks Total body

2. Wall sit Lower body

3. Push-up Upper body

4. Abdominal crunch Core

5. Step-up onto chair Total body

6. Squat Lower body

7. Triceps dip on chair Upper body

8. Plank Core

9. High knees/running in place Total body

10. Lunge Lower body

11. Push-up and rotation Upper body

12. Side plank Core

As noted earlier, mitochondrial degradation is a primary culprit in dwindling muscle mass. But recent evidence indicates that exercise can slow down this effect. According to Mark Tarnopolsky, a professor of pediatrics and medicine at McMaster University in Hamilton, Ontario, resistance training activates a muscle stem cell called a satellite cell. In a physiological process known as ‘gene shifting,' these new cells cause the mitochondria to rejuvenate. Tarnopolsky claims that after six months of twice weekly strength exercise training, the biochemical, physiological and genetic signature of older muscles are "turned back" by a factor of 15 to 20 years. That's significant — to say the least.

Studies involving middle-aged athletes indicate that high intensity exercise protects people at the chromosomal level as well. It appears that exercise stimulates the production of telomerase, what allows for the ongoing maintenance of genetic information and cellular integrity. Exercise also triggers the production of antioxidants, which boosts the health of the body in general.

And indeed, other studies are successfully linking athleticism to longevity. A recent analysis published in Deutsches Ärzteblatt International of more than 900,000 athletes (ranging in age from 20 to 79) showed that no significant age-related decline in performance appeared before the age of 55. And revealingly, even beyond that age the decline was surprisingly slow; in the 65 to 69 group, a quarter of the athletes performed above average among the 20 to 54 year-old group.

Essentially, exercise helps the body regenerate itself. This likely explains why older athletes are less susceptible to age-related illnesses than their sedentary counterparts. Moreover, ongoing exercise has been shown to preserve lean tissue, even during rapid and substantial weight loss. It also helps to maintain strength and mobility, which can significantly reduce risk of injury and stave off health problems that would otherwise linger.

Even more remarkable is how resistance training can stave off cognitive decline — what is arguably just as important as physical well being. In a study led by Teresa Liu-Ambrose of the University of British Columbia, women between the ages of 70 and 80 who were experiencing mild cognitive impairment were put through 60-minute classes two times per week for 26 weeks. They used a pressurized air system (for resistance) and free weights, and were told to perform various sets of exercises with variable loads. The results were remarkable: Lifting weights improved memory and staved off the effects of dementia. It also improved the seniors' attention span and ability to resolve conflicts.

With your talents and industry, with science, and that steadfast honesty which eternally pursues right, regardless of consequences, you may promise yourself every thing—but health, without which there is no happiness. An attention to health then should take place of evey other object. The time necessary to secure this by active exercises, should be devoted to it in preference to every other pursuit.

As an organ is exercised, circulation is more particularly directed to it and is more readily performed in it. Consequently, all its secretions and excretions increase. The more an organ is exercised, the more it is nourished.

1. GET ACTIVE: Inactivity can shave almost four years off a person's expected lifespan. People who are physically inactive are twice as likely to be at risk for heart disease or stroke.

2. KNOW AND CONTROL CHOLESTEROL LEVELS: Almost 40 per cent of Canadian adults have high blood cholesterol, which can lead to the build up of fatty deposits in your arteries − increasing your risk for heart disease and stroke.

3. FOLLOW A HEALTHY DIET: Healthy eating is one of the most important things you can do to improve your health -- yet about half of Canadians don't meet the healthy eating recommendations.

4. KNOW AND CONTROL BLOOD PRESSURE: High blood pressure − often called a 'silent killer' because it has no warning signs or symptoms − affects one in five Canadians. By knowing and controlling your blood pressure, you can cut your risk of stroke by up to 40 per cent and the risk of heart attack by up to 25 per cent.

5. ACHIEVE AND MAINTAIN A HEALTHY WEIGHT: Almost 60 per cent of Canadian adults are either overweight or obese − major risk factors for heart disease and stroke. Being obese can reduce your life span by almost four years.

6. MANAGE DIABETES: By 2016 an estimated 2.4 million Canadians will live with diabetes.Diabetes increases the risk of high blood pressure, atherosclerosis (narrowing of the arteries), coronary artery disease, and stroke, particularly if your blood sugar levels are poorly controlled.

7. BE TOBACCO FREE: More than 37,000 Canadians die prematurely each year due to tobacco use, and thousands of non-smokers die each year from exposure to second-hand smoke. As soon as you become smoke-free, your risk of heart disease and stroke begins to decrease. After 15 years ,your risk will be nearly that of a non-smoker.

Past experiments have shown persuasively that exercise spurs the birth of new mitochondria in muscle cells and improves the vigor of the existing organelles. This upsurge in mitochondria, in turn, has been linked not only to improvements in exercise endurance but to increased longevity in animals and reduced risk for obesity, diabetes and heart disease in people. It is a very potent cellular reaction.

[...]

Like muscles, many parts of the brain get a robust physiological workout during exercise. “The brain has to work hard to keep the muscles moving” and all of the bodily systems in sync, says J. Mark Davis, a professor of exercise science at the Arnold School of Public Health at the University of South Carolina and senior author of the new mouse study, which was published last month in The Journal of Applied Physiology. Scans have shown that metabolic activity in many parts of the brain surges during workouts, but it was unknown whether those active brain cells were actually adapting and changing.

To see, the South Carolina scientists exercised their mice for eight weeks. The sedentary control animals were housed in the same laboratory as the runners to ensure that, except for the treadmill sessions, the two groups shared the same environment and routine.

At the end of the two months, the researchers had both groups complete a run to exhaustion on the treadmill. Not surprisingly, the running mice displayed much greater endurance than the loungers. They lasted on the treadmills for an average of 126 minutes, versus 74 minutes for the unexercised animals.

More interesting, though, was what was happening inside their brain cells. When the scientists examined tissue samples from different portions of the exercised animals’ brains, they found markers of upwelling mitochondrial development in all of the tissues. Some parts of their brains showed more activity than others, but in each of the samples, the brain cells held newborn mitochondria.

There was no comparable activity in brain cells from the sedentary mice.

This is the first report to show that, in mice at least, two months of exercise training “is sufficient stimulus to increase mitochondrial biogenesis,” Dr. Davis and his co-authors write in the study.

Scientists have discovered that lactose, a byproduct of intense muscular activities, can be used to fuel the brain with energy. When glucose, the natural fuel of the brain, is no longer present in sufficient quantities, the cell tissue can “switch” to alternative energy, to prevent any damage to the brain on account of the lack of energy.

[...]

Consequently, by consuming the lactose in the blood, the brain clears the way for glucose, the main powering substance in the body, to reach the muscles and provide them with energy for the hard work they are doing. This research is very important because it explains why the brain is able to operate even when the body demands unusually high amounts of energy and oxygen. In fact, our mind actually goes into a higher “gear,” in order to be able to cope with any situation.

Lactate

Lactate is a negatively charged molecule formed from a compound called lactic acid. Some bacteria make lactate when they metabolize sugars. Humans also produce lactate as a byproduct of metabolism, though only under certain conditions. Specifically, says Dr. Gary Thibodeau in his book "Anatomy and Physiology," you make lactate when your cells process sugars for energy in the absence of oxygen, such as when you're engaging in a hard sprint or power efforts during exercise.

Lactate in Food

Lactate can occur naturally in some foods, and in other cases, it's added. Fermented foods like sourdough bread and yogurt contain lactate naturally. This is because these foods are manufactured by allowing bacteria to convert a certain amount of the sugar in the dough or dairy into lactate, yielding a sour flavor and change in texture. Because lactate changes a food's acidity, it can make it hard for pathogenic bacteria to grow in the food. As such, lactate is sometimes added to foods as a preservative.

Lactose

Unlike lactate, lactose is a sugar. While it's possible for humans, other animals and bacteria to convert lactose to lactate through the process of fermentation, the chemicals have little in common. You take in lactose any time you consume milk or other dairy products. An enzyme called lactase, which occurs in your intestines, digests lactose into smaller molecules that you absorb into your bloodstream and can use for energy, say Drs. Reginald Garrett and Charles Grisham in their book "Biochemistry."

Lactose Intolerance

Some people don't produce enough lactase to digest lactose effectively. This is referred to as lactose intolerance. If you're lactose intolerant, consuming dairy causes you to experience a variety of uncomfortable gastrointestinal symptoms, including bloating and cramping. If you're lactose intolerant, you have to avoid lactose-containing foods. Alternately, you can take a lactase supplement when you consume dairy. You do not, however, need to avoid foods with natural or added lactate.

Those who eat most, and who take the most exercise, are not in better health than they who eat just as much as is good for them; and in the same way it is not those who know a great many things, but they who know what is useful who are valuable men.

Scientists are also encouraged by studies on mice with a certain genetic mutation that makes them age prematurely — complete with graying and thinning fur, cataracts, hearing loss, smaller brains, enlarged hearts, anemia and thin and weak muscles — hallmark symptoms of growing older. To test whether it was possible to slow or reverse the process in these mice, a team led by Dr. Mark Tarnopolsky, a professor of pediatrics and medicine at McMaster University in Ontario, Canada, had the rodents exercise on treadmills three times a week from the age of 3 months to 8 months (about ages 20 to 55 in human terms).

In a 2011 study in the journal Proceedings of the National Academies of Sciences, the researchers showed that the exercise prevented many of the physiological symptoms of aging as well as premature death in the mice — to the point where they were indistinguishable from non-genetically altered mice.

"We protected not just the muscles — which people conceptually would say, 'Well, yeah, it makes sense that if you run, your muscles will be protected' — but even their cataracts, their kidneys, their gonads," Tarnopolsky says.

Similar results can be seen in humans. For 21 years, researchers at Stanford University have studied the effects of consistent exercise on 284 runners 50 and older. In a 2002 article in the Archives ofInternal Medicine, they reported that — 13 years into the study — a control group of 156 similar people who exercised much less on the whole than the runners had a 3.3 times higher death rate than runners as well as higher rates of disabilities.

In a 2008 study in the same journal, they reported that after 19 years, 15% of runners had died, compared with 34% of the control group. After 21 years, runners had significantly lower disability levels than non-runners; their death rates from cardiovascular events, cancer and neurologic disorders were much lower than in non-runners — 65 of the runners had died of cardiovascular, neurologic and cancer events compared with 98 deaths in the control group.

"You're 100 times better … as an athlete training in your 40s and 50s than a sedentary person in your 20s, any way you look at it," Tarnopolsky says.