By any measure, they were curious family outings.
After dark, 12-year-old Clyde Hertzman and his elder brother Owen would sprint, jog and walk the side streets of Vancouver's upper-middle-class Oakridge neighbourhood. Taped to their chests were portable EKGs.
Their mother, Eileen, drove beside them, while their father, an eminent cardiologist, sat in the back, collecting signals from the boys' varying heartbeats on a reel-to-reel tape recorder.
There was a purpose to Victor Hertzman's ordering of his sons about. By measuring recovery rates from different stresses on their hearts, he sought to strengthen his belief that carefully prescribed activity was better for heart patients than rest. Now accepted treatment, that was heresy in the early 1960s.
Their year or so as human guinea pigs left the brothers without chest hair, but the lesson of his father's homespun experiment was not lost on young Clyde.
The power of evidence to drive change formed the bedrock of a long, remarkable, groundbreaking career, one that ended suddenly on Feb. 8, when Dr. Hertzman died at the home of friends in London, England, of an apparent heart attack. He was six weeks shy of his 60th birthday.
His death prompted an outpouring of accolades from shocked colleagues who revered him, renowned researchers who marvelled at his work and organizations that embraced his conclusions.
Passionate, relentless in the pursuit of truth, boundlessly energetic and possessing a brilliant, incisive mind, Dr. Hertzman dramatically altered the way Canada and increasingly the world thinks about the importance of early childhood.
In study after study, he demonstrated that the circumstances of a child's first few years are critical to future development, right through to old age. Low socioeconomic status, poor parenting, stress, lack of stimulation before one turns five could stunt a person's life forever.
The theory was not new, but not until teams headed by Dr. Hertzman amassed broad-based data identifying the risk levels of children entering the school system did it really take root.
As his research evolved, Dr. Hertzman coined the now widely used term "biological embedding" to describe how early environment is more a determinant of a child's future behaviour than genetic makeup.
"Early social experiences get under the skin to set a lifelong trajectory for health and well-being," explained Alan Bernstein of the Canadian Institute for Advanced Research. "Clyde played a central role in creating a framework to understand that."
His worldwide reputation was recognized in 2005, when the World Health Organization set up an international commission on the social determinants of health. Dr. Hertzman was asked to head the section on early childhood development.
"He wasn't the first person to show that it is important for adult health, but Clyde made it important," said commission chairman Michael Marmot of University College in London. "He synthesized the material. He showed how important it was in a population health context."
In 2010, the Canadian Institutes of Health Research named Dr. Hertzman "health researcher of the year," providing him with a grant of $500,000.
At the end of December, he was named an officer of the Order of Canada, an award that touched him deeply.
"It was recognition," said his partner, Marcy Cohen. "When you are someone passionate like Clyde, who doesn't dress in suits, and doesn't always win the favour of the establishment, you suffer from that at times. The Order of Canada was extremely important to him."
A professor for more than 25 years in the School of Population and Public Health at the University of B.C., Dr. Hertzman also held a number of prominent research chairs and directed the Human Early Learning Partnership, comprising academics from six B.C. universities dedicated to leading-edge research on early childhood development.
Born March 24, 1953, Dr. Hertzman was the younger of two sons of Victor and Eileen, an accomplished pharmacologist.
The brothers were highly active teenagers, whether trolling for salmon along remote stretches of the West Coast, or, despite their short stature, tearing up the football field. At one point, Owen said, the pair sidelined Michael Campbell, brother of former premier Gordon Campbell and well-known financial analyst, with a crunching tackle.
As the turbulent 1960s ended, however, Clyde was caught up in hardline politics. At 17, hair down to his waist, he moved into a collective house and joined the radical Vancouver Liberation Front, scourge of mayor Tom Campbell, who threatened to unleash the War Measures Act against the ultraleft organization.
Among those sharing the house was 24-year old Marcy Cohen. The two became close friends, then drifted in different directions. Much later, Ms. Cohen and Dr. Hertzman rekindled their friendship, and began a relationship.
While he soon dropped the ideology of his early politics, Dr. Hertzman did not abandon his unwavering belief in egalitarianism and a fair society. He simply decided he could accomplish more working within the system.
In 1975, he enrolled in medical school at Hamilton's McMaster University, a hotbed of dynamic academic thinkers bent on gathering evidence to upend the status quo and improve health outcomes.
Dr. Hertzman graduated in community medicine, and immediately focused on occupational and environmental health. "He wasn't interested in becoming rich. He wanted to do research," said fellow health researcher Michael Hayes, who became one of Dr. Hertzman's closest friends.
During his time at McMaster, a counsellor thought her daughter, Martha Ellis, recently returned from B.C.'s Hornby Island, might hit it off with the talented young med student. She was right.
The couple married in January, 1977. By 1982, they had three children – Amos, Emily and Eric. The Hertzmans separated in 1999.
Dr. Hertzman was not destined to stay in occupational and environmental health, nor in Hamilton. Bright and committed, he came to the attention of Canada's great visionary on the social determinants of health, Fraser Mustard.
Dr. Mustard sold the budding activist scholar on the importance of early childhood development and population health, the idea that conditions should not be studied in isolation but within the context of a broad spectrum of social and economic conditions.
It was a calling that consumed Dr. Hertzman for the rest of his life.
He put his stamp on the field with a landmark project in 2000 that enlisted kindergarten teachers across Vancouver to assess their young charges in five key areas: physical well-being, social competence, emotional maturity, language and communication. They did so using a lengthy, multiquestion scorecard known as the Early Development Instrument (EDI).
Results were then applied across 23 neighbourhoods and rated on colour-coded maps according to the percentage of kids deemed at risk in a least one of the five EDI categories. Not unexpectedly, lower-income neighbourhoods fared poorest, but surprising numbers of vulnerable kids also surfaced in middle-class and upper-class areas.
When the detailed neighbourhood maps appeared in the newspaper, "all hell broke loose," Dr. Hertzman recalled later. "You saw these huge differences."
The impact was profound. Other school districts clamoured to be assessed, too. Since then, three provincewide surveys have been conducted. Use of the EDI has now spread to 80 per cent of Canada's kindergarten population and to 15 countries.
The latest B.C. results showed more children were vulnerable than in 2000, a factor Dr. Hertzman attributed to increasing stress on parents, forced by the recession to work harder and longer to make ends meet.
It frustrated him that, despite his findings, Canada continues to scrimp on preschool-age children. There is no national daycare program, kindergarten is not mandatory in many provinces, and parental leaves are not long enough. "Canada is one of the worst investors in early childhood development," he complained in 2007, adding that each dollar spent on a child before the age of six is estimated to save six dollars down the road.
Dr. Hertzman's death stilled one of the country's strongest voices for better treatment of children. It was his great cause, and he made dozens of speeches every year, attending high-powered conferences as well as visiting small communities throughout B.C., espousing its importance.
"He brought a body of knowledge that was somewhat sequestered and really mainstreamed it," said Jim Dunn, an associate professor at McMaster, who worked with Dr. Hertzman. "He was absolutely tireless."
Those who knew him well stress he was just as captivating in private. He was great fun to be around, with an immense thirst for life. Last Christmas Eve, there he was, a Jew, striding up and down the street singing carols with Michael Hayes and his family in Victoria. "He will be sorely, sorely missed," said Mr. Hayes.
Owen Hertzman clings to a different memory. "The day before he died, two crocuses opened up in our garden. I will always remember that," he said.
Dr. Hertzman leaves his mother Eileen, brother Owen, partner Marcy Cohen, children Amos, Emily and Eric, and three grandchildren.