Multi-Disciplinary Reading – Book Reviews

Exercised, Daniel Lieberman, 2020 – Its not like we don’t know exercise is beneficial but why is it so hard to start and even harder to persist? This book has a great perspective on exercise from multiple vantage points, empathizing with our inability to get started and yet emphasizing on why we should.

My notes –

• We never evolved to exercise. No one ever walked or ran several miles just for health

• Exercise is big business – with special clothes, equipment, memberships and events

• “Wanting” to exercise is a myth, despite what “exercicists” claim. Our natural instincts avoid optional exertion

• Tarahumara Native American tribe even today run unimaginable distances – they don’t train for this (they find it preposterous), and are not built for it either (non-athletic frames). They run once a year – just like that, for up to 70 miles – its a deeply spiritual ceremony, a powerful form of prayer for them

• Tarahumara tribe on average walks foraging for 10 miles a day – this is their “training”

• Genes play key roles in sports and exercise, including our “motivation” to

• Truthiness – Something that feels true because we want it to

• WEIRD – Western, Educated, Industrialised, Rich and Democratic (96% of studies on exercising and behavior comes from this sample)

• Hadza tribe does light activities for 2.5 hours and vigorous activities for 3.5 hours – rest of the time is spent “resting”

• PAL – Physical Activity Level = Energy spent in a day / Energy spent by body at rest. PAL is 1.4-1.6 for sedentary office workers. Hunter-gatherers avg 1.8-1.9. Factory workers and farmers about 1.8 (An hour or two of walking would make you as active as a hunter gatherer)

• RMR – Resting Metabolic Rate – about 70 cal/hr while resting in a chair for a 82 kg adult (1700 cal/day for doing nothing). This is flexible (will be lower when you starve – body adapts)

• BMR – Basal Metabolic Rate – Adjusts for energy spent in balancing, digesting, regulating body temp. Etc in RMR (so measure it after you woke up from sleep). Usually 10% lower than RMR

• People who work sitting down get paid more than those that work standing up (Ogden Nash)

• Standing costs 8-10% more calories than sitting down

• People who rarely sit on chairs have 21-41% stronger backs. Weak backs lack endurance and increases chair dependency (vicious cycle)

• Every hour spent sitting is 1. an hour not spent being active, 2. Harmfully elevates sugar and fat in bloodstream 3. Triggers our immune system to attack our bodies (inflammation)

• Chronic low grade inflammation from sitting can attack organs by damaging tissues and lead to type-2 diabetes and heart disease

• Fat is stored subcutaneously (under the skin) or on organs. Organ fat up to 1% of body weight is OK and helps in quick burst of energy but more can mess with metabolism, attract WBCs and trigger cytokine inflammation (paunch is a tell-tale sign of organ fat)

• Instead of sitting, engage in low-intensity non-exercise physical activities for 5-6 hours (Equivalent to 1 hour of running)

• Post-prandial state – upto 4 hours after meal. Body is busy digesting and transporting fats and sugars. Important to move at least moderately during this period to avoid excessive fat storage

• Cortisol from stress also makes us crave sugar and fat rich foods (and stores organ fat)

• Take breaks from sitting and move around, squat briefly often. This fights low-intensity inflammatory fire

• To avoid back pain from sitting, posture alone doesn’t help – a strong back begets a better posture

• Sleep, along with physical activity has declined alongside the industrial revolution

• Zebras sleep only 3-4 hrs a day while a lion sleeps 13 (prey animals vs carnivores)

• Lack of sleep induces stress (vicious cycle), depresses immune system and stores more organ fat and wreaks havoc in digestive hormones

• Sleeping pill usage in American adults has tripled since ‘98

• Energy for short bursts comes from creatine phosphate (CrP). Next from glycolysis of sugar molecules (quick snipping of bonds to recharge ATP). (Fit human can run 15 miles from this sugar snipping). These two processes don’t need oxygen. Burning sugar however liberates 18x more energy from sugar but needs oxygen. (If you want to run far) Energy from body fat takes more steps and hence more time to use.

• Higher VO2 max helps you run far. 30s sprints it doesn’t matter. 10% energy is from aerobic respiration in a 100m dash. 30% for 400m and 60% for 800m and 80% for a mile

• White and red muscle fibres are fast and slow twitch respectively. White/fast helps sprinters while red/slow helps long-distance runners (proportions of each varies by training) – thats why Usain Bolt might struggle long-distance

• HIIT – High-intensity Interval Training. Short bouts of intense exercise like sprinting with less intense periods for recovery – sprinter faster without compromising endurance

• HIIT increases heart’s ability to pump blood – chambers larger and more elastic, improves muscles ability to transport glucose

• CrossFit – alternate intense cardio with equally intense resistance exercises (kettlebell, handstand pushups, climbing ropes)

• Strength vs Power – how much force I can produce vs how rapid can I produce it. There’s a tradeoff between the two. We benefit more from the latter than former in everyday life

• Resistance exercise – force such a body’s weight or external load like dumbbell or weights that resist your muscles’ effort to contract (Concentric, isometric or eccentric contraction – first helps with movement while latter with strength)

• After 3 weeks of bed rest, leg muscles can shrink upto 10% (astronauts lose 20% in 2 weeks). As we age muscle fibres dwindle in size and count (atrophy). Grip strength reduces by 25% between 25-75

• Due to decline in muscle mass, people load their bones less, leading to osteoporosis (not to mention heart disease and type-2 diabetes from less physical activity)

• We didn’t evolve to exercise but to be physically active, like walking. We would also carry loads half of our body weight (lugging wood, children, water etc.). Walking is poor for weight-loss (can take more than half-hour per day for many months or years, since it is very efficient on calories)

• Dieting vs Exercise – cutting down 700 cals vs exercising 700 cals had same effect on weight loss – but exercise reduced organ fat as well so is preferred

• If you are in 30s or 40s, lacking endurance to run – start by walking and running – first a quarter mile, then half, then 1 mile, then 2 and so on – mix walking and running – you can do 5 miles a day jog comfortably even when you are old

• At rest, heart pumps 4-5 lts of blood per min. While running it can go up 4-5x more

• Long periods of vigorous exercise like running can stimulate opioids, endorphins and cannabis like chemicals (runner’s high)

• Long post-reproductive lifespans are rare in the animal world but humans evolved to it. Active grandparents help alleviate the load on foraging mothers and hunting fathers and help raise children

• Relationship between death (mortality) and illness (morbidity) – hunter-gatherers stay healthy until they die – health span and lifespan overlap – industrial humans have lengthening lifespan with a worsening health span (healthy until 50 but living till 80 – exercise can keep you healthy till 75 while living till 80)

• Exercise is done against one’s wishes and is maintained only because the alternative is worse

• Dopamine, serotonin, endorphins (20mins or more of vigorous exercise) and endocannabinoids (several hours of physical activity) reward us for our activity

• Prescription – 150 mins of moderate-intensity (50-70% of max heart rate) or 75 mins of vigorous-intensity (70-85% of max heart rate) aerobic exercise per week (walking, jogging or cycling) with two sessions of weights (working all muscle groups – legs, hips, back, core, shoulders and arms)

• Benefits of cardio – stronger, supple heart, higher volume of plasma (less viscous blood), clear unclogged arteries, raises HDL and lowers LDL and keeps resting BP low. Also inc. muscle fibres, burns organ fat, improve burning sugar, lowers inflammation, improves bone density, stimulates immune system and improves cognition and mood. Few mins of HIIT (say sprinting, stair-running) can have same benefits as 30mins of aerobics

Regular physical exercise helps slow ageing and prolong life. Bridging the health span and life span is very important if we are to live our 50-80s happy instead of grudging our existence. I got this book to motivate myself to get started (and I did). It has made me mindful on several aspects and I high recommend reading it alongside “why we sleep” and “breath”. 9/10