Homo Deus – review and quotes

Although sub-titled A Brief History of Tomorrow, in reality most of this book covers how we – humankind and society – have got to where we are today. Possibly old hat stuff for historians and sociologists but I found the subject matter a useful summary of the key phases of societal development including how modern day corporations and governments are the intersubjective entities that have replaced religion.

The overview of humanism and discussion of capitalism v communism then leads on to the main point of the book, Dataism – the concept that the important thing in the universe is data processing, and once AI can do it faster than humans there may be no need for our existence any longer. However, this future development is only covered relatively briefly so look elsewhere if you want to really dig into this concept.

Quotes from the Homo Deus: A Brief History of Tomorrow

Life expectancy
For the first time in history, more people die today of eating too much than from eating too little; more people die from old age than from infectious diseases; and more people commit suicide than are killed by soldiers, terrorists and criminals combined.

Aging research
Yet because old age and death are the outcome of nothing but particular problems, there is no point at which doctors and scientists are going to stop and declare: “Thus far, and not another step.”

Maximum lifespan
In truth, so far modern medicine hasn’t extended our natural lifespan by a single year. Its great achievement has been to save us from premature death, and allow us to enjoy the full measure of our years. Even if we now overcome cancer, diabetes and the other major killers, it would mean only that almost everyone will get to live to ninety – but it will not be enough to reach 150, let alone 500.

Hi-tech gurus are brewing for us brave new religions that have little to do with God, and everything to do with technology. They promise all the old prizes – happiness, peace, prosperity and even eternal life – but her on earth with the help of technology, rather than after death with the help of celestial beings.

Buy on Amazon: Homo Deus: A Brief History of Tomorrow by Yuval Noah Harari

Water – No Need To Overdo It

As part of my research for the Live Forever Manual I thought drinking plenty of water would be an obvious tip, but the evidence wasn’t clear enough that it extended life. So it hasn’t made it as a practical tip in the book, though there are plenty of benefits from keeping well (but not overly) hydrated.

The 8 glasses of water per day rule came from a 1945 recommendation stating that a suitable water allowance for adults is 2.5l/day in most instances. However internet, sports and nutrition media tend to present these quantities as plain water ignoring the fact that most of those fluids are regularly consumed in everyday meals and drinks. One of the probable reasons for hydration becoming a popular issue presented by media and regulatory bodies was the increase in the consumption of caloric beverages, which has contributed to obesity prevalence worldwide. This isn’t an issue in the UK, as one epidemiological study found that total fluid intake was mostly comprised of hot beverages, followed by water.

water - no need to overdo it

Water certainly is an essential component of our diet in so many ways. Firstly, it controls body temperature through fluid loss (sweating). The second essential feature is regulation of kidney function as kidneys use water to filter waste from the bloodstream and excrete them via urine.

Some smaller-scale studies also found that bad hydration may be linked with adverse cardiovascular health as it is involved in regulation of blood volume which is closely associated with blood pressure and heart rate. Blood volume is tightly regulated by the water intake/output ratio, which means that loss of body water will also decrease the blood volume, that way affecting other elements of the cardiovascular cascade.

Although gastrointestinal health is largely affected by bad dietary habits, it is also seen that inadequate water intake is a common culprit in constipation problems. Enhanced water intake is recommended in those problems as it can enhance gastrointestinal transit, however, evidence suggests that people respond differently. That is because some people are in hypo-, hyper and euhydrated state. The only usefulness of this treatment is seen in individuals that are in hypohydrated state not in those that are well hydrated.

Large observational studies found that water deprivation may affect cognitive performance, impair concentration, increase irritability and prolong migraines. The mechanisms underlying the associations between water intake and cognitive performance are not well studied, but there are indicators that mild dehydration may physiologically stress the body and compete with cognitive processes. it has been proposed that mild dehydration acts as a physiological stressor which competes with and draws attention from cognitive processes.

Skin health and moisture is often linked with proper water consumption, and this was confirmed in clinical trials in which 2L of mineral water/day had an impact on these features. Again, the significant results were obtained in the group that was already less hydrated and not in people that were euhydrated.

It is noteworthy to mention that water requirements vary greatly depending on the climate zone (people living in hot climates have higher requirements than those living in colder temperatures), while there is also a big difference between sedentary people and those performing some physical activity. People who have regular exercise in hot conditions and no adequate fluid replacement are at higher risk of hyperthermia, reduced stroke volume and cardiac output, while they also tend to experience decreases in blood pressure and reduced blood flow to muscle.

Yes, reasons for good hydration are plenty, however, a lamp of evidence reports conflicting results, that way suggesting that recommendations and alarms from the media are overreacting. Large population-based studies do not support the notion that we should drink 2 or more litres of water per day. As a matter of fact, one of them concluded quite the opposite – women that drunk higher amounts of water had a lower survival rate than those drinking less. One population-based cohort also failed to confirm that high water intake may lower the risk of kidney dysfunction and cardiovascular diseases in older adults (average age of 70.3), nor in men aged 55-75. But in another large-scale study they found a significant negative association between water intake and the risk of fatal coronary heart disease (which was more pronounced in men), while women with higher intake of fluids other than water were more likely to become ill.

Finally, animal-studies data were pointing out that inadequate urination may prolong the contact time between carcinogens and urothelium thus enhancing the risk of bladder cancer occurrence. One large-scale prospective study supported the notion that men should drink 2.5 l of water daily in order to lower the risk of bladder cancer.

So, according to the science we should definitely pay attention to our hydration status, however, bear in mind that you consume fluids through your regular diet too.

Aging Biomarkers – Chronological v Biological Age

Chronological age can be defined as the time measured from an individual’s birth to a particular date. Biological age is more complex, since it positions an individual within its own lifespan and probability of survival, meaning that a 67 year old man with a biological age of 60 is more likely to live longer than a 67 year old man with a biological age of 70. These concepts are related and in some cases the values can be equal but they are not the same thing.

Chronological age is simply a number representing the length of someone’s life to a particular point; therefore it is difficult to associate biomarkers to it since any biomarker with any influence in the capacity for survival would immediately be more related to biological age. A strict chronological age biomarker should be a biological feature that changes over an individual lifespan but doesn’t directly affect the probability for survival.

There are several biomarkers currently being used that don’t influence survival greatly and are related to older individuals, these could be easily called “chronological age biomarkers”. Reduction of the coronal pulp cavity (using radiography) is a very common method used in forensic science, however, in adults most signs of aging like wrinkles and silver hair are features that can manifest at different points in someone’s life and won’t be useful to accurately determine someone’s biological age.

When looking for aging biomarkers that will reveal the biological age of an individual, these can be split between functional (macro) and physiological (micro) biomarkers.

Aging Biomarkers Infographic

Biological Biomarkers

After many decades of research, the scientific community now agrees on 9 hallmarks of aging that relate to physiological processes acting at the cellular level. These are: accumulation of genetic errors due to genomic instability, telomere attrition or degradation, epigenetic alterations, damage of the internal mechanism in charge of quality control for protein synthesis, deregulated nutrient sensing, mitochondrial dysfunction, loss of the capacity to grow and change stem cell exhaustion and altered intercellular communication.

All of the physiological biomarkers considered above provide data about the capacity of the organism to sustain operation of its own processes over time and also about its capacity to withstand different forms of stress.

These nine hallmarks of aging are robust candidates to be considered for any system dedicated to the determination of biological age; however, obtaining accurate measurements of any of them requires a lot of specialized equipment and capable staff, since they cannot be evaluated easily. Some of them like stem cell exhaustion or mitochondrial dysfunction can only be measured by taking a biopsy and performing a longitudinal study in vitro under laboratory conditions, something that most laboratories don’t provide as part of their usual services.

Functional Biomarkers

Fortunately, functional biomarkers are easier to measure and are considered equally valid to measure biological age. These cover both cognitive and physical performance and include visual acuity (Snellen chart), auditory acuity (pure tone audiometry), decision reaction time, grip strength (dynamometers), body mass index (height and weight measurement), blood pressure (systolic and diastolic pressure), lung capacity (spirometer) and memory.

Functional age is a specialized form of biological age, is task-oriented, and can provide valuable information in regards to an individual’s capacity to perform a particular task or its vulnerability within a certain set of conditions.

All biomarkers mentioned in this article have shown correlation with the process of aging in the past, however, a system designed to provide an accurate value for someone´s biological age will have to integrate a large number of these variables at the same time and incorporate an elegant method to accumulate, process and interpret data from a considerable amount of sources.