direct interaction between the health of the body overall and brain health. The two are tightly intertwined. The critical energy supply to the brain is provided by the microvascu- lature, the small brain blood vessels and the neurovascular unit, which are the first to suf- fer impairment in the context of poor physical form. Small- vessel disease is now regarded as the underlying neuropathological process and earliest pathophysiological process of many dementias and hence it becomes critical to investigate vascular factors and pathol- ogy before the disease escalates and becomes irreversible [25]. Much clinical and basic sciences research supports physical exercise as a major factor in the prevention of demen- tia and cardiovascular disease. An impressive study that was scientifically rigorous, the Caerphilly study, included, in addition to PE, other factors as well, such as smoking ces- sation, weight control, and healthy eating. However, of these, physical exercise was the most powerful, with specific example exercises being two miles of walking or ten miles of cycling per day. This study reported a 60 percent reduction in mild cognitive impairment (MCI) and dementia, a 50 percent reduction in both vascular disease and diabetes, and a 60 percent reduction in the all- cause mortality category [26].
Some occupations demand a certain entry level of fitness capabilities (Table 10.1).
However, basic brain and body fitness is a prerequisite for all who make decisions for themselves and who are entrusted with others, whether a parent, spouse, company CEO, or national figurehead.
Scientific research has revealed that the following effects of PE may be realized:
Hardware
1. brain chemicals are released (BDNF) that stimulate brain growth;
2. neurogenesis or new brain cell formation;
3. synaptogenesis or new connections are formed;
4. angiogenesis or new brain blood vessel formation [27].
Software
1. improved working memory (the brain’s operating system);
2. improved episodic memory;
Table 10.1 Physical exercise perspectives of specific job fitness requirements
Federal Bureau of Investigation (FBI) fitness test for men 20–29 (less for women and less for older age categories)
Push-ups, minimum in 1 min 29
Sit-ups ≤1 minute 38
Sprint, 300 m ≤59 s
Run 1.5 miles ≤12.5 min
Navy Seals entry level requirements (competitive level differs)
Push-ups, minimum in 2 min 42
Sit-ups, minimum in 2 min 50
Swim 500 yards ≤12.5 min
Pull-ups minimum no time limit 6
Run 1.5 miles (boots, long pants) ≤11.5 min
Physical Exercise 161
3. improved attention;
4. improved executive function.
Feel-good neurotransmitters released 1. brain “marijuana” (endocannabinoids);
2. brain “morphine” (opioids).
Feel-good effects
1. alleviation of depression;
2. alleviation of anxiety;
3. improved sleep (adenosine production).
Reduction in the top four major diseases 1. dementia (~50 percent reduction);
2. cardiovascular disease;
3. strokes;
4. cancers [28,29].
What Happens When You Don’t Exercise?
1. Brain atrophy (shrinkage) that correlates directly with obesity.
2. Speed of information processing decreases (word finding and memory problems).
3. Executive function decreases (the PFC is more sensitive to effects of aging compared to other brain areas and has the most rapid age- related loss in volume; it is also the region most sensitive to more physically active lifestyles).
4. Weight gain and increased BMI lead to vascular (heart attack, stroke, kidney, retinal disease) and/or metabolic conditions (diabetes), which in turn affect all organs.
5. Depression [30,31].
Side-Effects of Exercise
In addition to the beneficial effects, as with any intervention, adverse effects may occur.
Endocannabinoid and opioid production lead to your own natural high that is safe and with minimal side- effects [32,33]. Side- effects may result as a consequence of the natur al high experienced after moderate to intense exercise, sometimes called the “runner’s high,” leading to unrestrained exercise. This results in overuse injuries and withdrawal states when injury renders one unable to exercise.
Type of Exercise: Physical Activity (PA) and Physical Exercise (PE)
1. PA refers to the monitoring of non- exercise activity only, measured by tri- axial accelerometers, referred to as actigraphy.
2. PE refers to specific exercises to improve overall fitness, and is monitored by fitness devices that include time, speed, and distance parameters.
3. PE may be monitored by more advanced measurements such as VO2 max (the maximum rate of oxygen consumption during intense exercise, where V = volume, O2 = oxygen, max = maximum), measured in milliliters of O2 per minute per
kilogram of weight; lactate threshold is useful for competitive athletes and those who are able to participate in high- intensity aerobic exercises.
How to Exercise
Screening
Screening is important before you start and should include the following:
1. Cardiovascular assessment encompassing:
a. ECG rhythm strip b. cardiac stress testing;
2. physiotherapy consultation for:
a. balance b. coordination
c. musculoskeletal status.
Basic PE Components
1. aerobic (becoming cardiovascular fit – running, cycling, swimming, kayaking);
2. anaerobic (improving fitness – interval training sessions);
3. strength training (this has many benefits, including hypertension and weight reduction);
4. yoga (improves flexibility, stretching, correcting muscle imbalance due to specific sports);
5. balance.
Electronic Monitoring Devices
1. actigraphy devices: Nike Fitbit, Withings Pulse Monitor
2. GPS-based devices: Garmin, Apple Watch, chest heart rate monitoring.
Exercise Intensity
Exercise intensity is guided by maximum heart rate (MHR) percentage, subjective exer- tion and benefits. Calculation of MHR for a particular age and gender is by the following formula:
MHR = 217 – (0.85 × age)
A simplified version of MHR by the CDC target heart rate formula can be used (220 – age). For moderate- intensity physical activity one should aim for 50–70 percent of MHR.
For example, the MHR of a 50-year-old person would be 220 – 50 = 170; therefore, the moderate- intensity levels for a person aged 50 would be:
• 50 percent: 170 × 0.50 = 85
• 60 percent: 170 × 0.60 = 102
• 70 percent: 170 × 0.70 = 119.
Thereafter the intensity of exercise, using running as an example, is evaluated according to the individual heart rate parameters (mild, moderate, intense):
• Mild: MHR 50–60 percent. Relatively easy pace of activity with regular breathing and early, aerobic/cardiovascular training effects.
Physical Exercise 163
• Moderate: MHR 60–70 percent. The pace remains comfortable, conversation possible, breathing deeper and more frequent, increased aerobic training effects.
• Moderate: MHR 70–80 percent. Moderate pace, more difficult to hold conversation, optimal aerobic/cardiovascular training.
• Intense: MHR 80–90 percent. Further increase in pace, with more labored breathing, leading to improved anaerobic capacity and improvements of speed of individual activity.
• Intense: MHR 90–100 percent. Sprinting pace, cannot sustain for long periods, labored breathing, with anaerobic benefits, increased muscular power and endurance.
Measurements of PA
PA, or basic movement, can be measured by number of steps taken per day using an actigraphy device:
• sedentary: <5000
• low activity: 5000–7499
• somewhat active: 7500–9999
• active: 10 000–12 499
• highly active: ≥12 500.
Metabolic Equivalent Approach to Exercise
By way of brief overview, quiet sitting is considered 1 MET (metabolic equivalent); sleeping is rated at 0.9; and walking at a slow pace is rated at 2. An approximate range of MET values vary from 0.9 (sleeping) to 23 (running at 22.5 km/h or a 4:17 minutes per mile pace). From a scientific point of view, 1 MET is defined as the amount of oxygen consumed while sitting at rest and is equal to 3.5 ml O2 per kilogram of body weight × time (minutes) (3.5 ml O2·kg−1·min−1) or one MET is 58.2 W/m2. A convenient grading scale is:
• light: <3.0
• moderate: 3–6
• vigorous: ≥6.
We can compute weekly METs/per hour × hours per week (aim for 9–15 hours per week) or minutes per week (aim for 500–1000 minutes per week). Table 10.2 offers some ex amples of activities and their METs.
Advanced Measurements Used by Athletes
• VO2 max estimation
• vVO2 max estimation
• lactate threshold
• beat to beat
• stress monitoring.
VO2 max is an accurate and objective measure of fitness as it calculates aerobic endur- ance and cardiovascular fitness. It may be conceived as a kind of “horse power” of your cardiovascular system. Various formulas exist for this measurement:
• VO2 max estimation by the Uth–Sorensen–Overgaard–Pedersen test: VO2 max = 15 × HR max/HR rest;
Table 10.2 Example METs
Activity MET/hour of activity
Walking (km/h)
slowly 2.0
6.4 5.0
7.2 7.0
Running (km/h)
10 10.0
13 12.9
15 14.6
Cycling (km/h)
15 5.9
20 7.4
25 8.4
30 9.8
Swimming (km/h)
2 4.3
2.5 6.8
3.0 8.9
3.5 11.5
4.0 13.6
Kayaking/rowing (km/h)
8 10.3
12 13.5
16 16.4
20 19.1
Selected sports/activities
Weight training 10.9
Yoga 3.2
Fishing from bank 2–3
Fishing from stream 3–4
Gardening 4.4
Shoveling snow 5.1
Housework 5–7
Alpine skiing 5–9
Aerobic dancing 6
Volleyball 6
Tennis 6–8
Fencing 6–10
Equestrian 7
Curling 7.4
165 Physical Exercise
• Cooper test: VO2 max = d12 – 505/45 (d12 is distance in meters covered in 12 minutes) [34].
Table 10.3 offers some average VO2 max values.
• VO2 max and cognitive function: In addition to athletic fitness, exercise has both general and specific effects on cognitive function:
– general: several different cognitive domains improve after months of aerobic exercise;
– specific: executive function is improved more than other cognitive domains.
Functional neuroimaging research has shown that white matter connectivity improves with better VO2 max, and that lower microstructural integrity of brain white matter is related to higher mortality [35]. The volume of white matter hyperintensities has also been correlated with decreased cognitive functioning [36].
vVO2 max estimation is a measure of efficiency of your body. Although your VO2 max or the “horse power” of your cardiovascular system is important, how efficiently your body transfers this power to overall speed via the legs or arms is what counts – hence velocity at VO2 max is reported in units of speed, typically meters per second. The velocity at maximal oxygen uptake (vVO2 max) is the peak running pace that can be maintained for an average of about six minutes running at maximal oxygen uptake. For a trained athlete, this may be a four-minute-mile pace or running at about 24 km/h or more. The vVO2 max measurement is therefore dependent on VO2 max as well as running economy.
Heart rate variability (HRV) can be easily measured using a number of wearable elec- tronic devices. It reflects autonomic control of the cardiovascular system, with an increase in variability when parasympathetic activity dominates and a decrease with increased sympathetic activity. HRV can be used as an indicator of daily stress in a person’s life, allowing an early and appropriate adjustment. HRV can also be used as a prognostic indicator in cardiac syndromes such as heart failure and acute myocardial infarction [37].
Fitness age is a very convenient and effective method of rapidly computing a person’s biological – as opposed to chronological – age. Using a formula with inputs from resting and maximal heart rates, waist circumference at the level of the navel, age, gender, and amount and intensity of physical activity, a fitness age number is generated which may be older or younger than the chronological age. Typically, fit elderly people may be one or more decades younger by fitness age! The website for this calculation can be found at www.ntnu.edu/cerg/vo2max. These formulas are based on the estimated cardiorespiratory fitness researched by the Norwegian University of Science and Technology group [38].
Table 10.3 Some notable values of VO2 max in ml/kg2/min
Example VO2 max
Low-fitness human 11
Average untrained man 35–40
Average untrained woman 27–31
High-fitness human 50
Best human Olympic athlete 96
Cheetah 130
Siberian Iditarod dog 240
Pronghorn antelope 300
Recommended Key Performance Indicators
Measuring and monitoring by you:
1. Overall activity measured in metabolic equivalents (MET). Some examples of a MET per hour: sitting, 1; slow walk, 2; Yoga, 3.2; brisk walk, 3.5; cycling, 7.5; swimming, 9; weight training, 10; running, 10; kayaking, 10; sprinting, 23. Aim for 9–15 MET hours per week.
2. You can record the number of steps per day (for example, 10 000 is good) with smartphones or electronic fitness devices.
3. Keep a log of timed distance and speed data from activities you do, such as walking, running, swimming, cycling, or kayaking with the aid of electronic monitoring devices (e.g., Garmin, Fitbit).
Measuring and monitoring by medical professionals:
1. Garmin devices measure VO2 max.
2. VO2 max may also be computed using the formula VO2 max = 15 × HR max/HR rest (Uth–Sorensen–Overgaard–Pedersen test).
3. VO2 max can be computed using VO2 max = d12 – 505/45 where d12 is distance in meters covered in 12 minutes (Cooper test).
4. vVO2 max estimation is used for competitive athletes. The vVO2 max is computed by measuring the distance run in meters at maximum heart rate for a time of 6 min, and is recorded in meters per second.
5. Measure heart rate variability (HRV), which allows estimation of stress monitoring by specific Garmin devices (Vivoactive 3).
6. Record fitness age as a comparison to your biological age (Garmin devices) or from the website www.ntnu.edu/cerg/vo2 max.