Note on the effect of external temperature on the circulation in man

A century of exercise physiology: concepts that ignited the study of human thermoregulation. Part 3: Heat and cold tolerance during exercise

In this third installment of our four-part historical series, we evaluate contributions that shaped our understanding of heat and cold stress during occupational and athletic pursuits. Our first topic concerns how we tolerate, and sometimes fail to tolerate, exercise-heat stress. By 1900, physical activity with clothing- and climate-induced evaporative impediments led to an extraordinarily high incidence of heat stroke within the military. Fortunately, deep-body temperatures > 40 °C were not always fatal. Thirty years later, water immersion and patient treatments mimicking sweat evaporation were found to be effective, with the adage of cool first, transport later being adopted. We gradually acquired an understanding of thermoeffector function during heat storage, and learned about challenges to other regulatory mechanisms. In our second topic, we explore cold tolerance and intolerance. By the 1930s, hypothermia was known to reduce cutaneous circulation, particularly at the extremities, conserving body heat. Cold-induced vasodilatation hindered heat conservation, but it was protective. Increased metabolic heat production followed, driven by shivering and non-shivering thermogenesis, even during exercise and work. Physical endurance and shivering could both be compromised by hypoglycaemia. Later, treatments for hypothermia and cold injuries were refined, and the thermal after-drop was explained. In our final topic, we critique the numerous indices developed in attempts to numerically rate hot and cold stresses. The criteria for an effective thermal stress index were established by the 1930s. However, few indices satisfied those requirements, either then or now, and the surviving indices, including the unvalidated Wet-Bulb Globe-Thermometer index, do not fully predict thermal strain.

Joseph Barcroft, 1872-1947

Joseph Barcroft, or J.B. as he was so widely known, was born on 26 July 1872 at the Glen, Newry, Co. Down, Northern Ireland. He was the second of the five children of Henry and Anna Barcroft; his eldest sister, Sarah, died a fortnight after his own death on 21 March 1947 and of a similar heart complaint. His younger brother, David Barcroft, M.D., had already died a few years earlier; his two surviving sisters, Mary and Netta, still live in the old home. The Barcrofts were originally an old Lancashire family. J.B.’s ancestor, Ambrose Barcroft of Foulbridge Hall, had three sons, Thomas, Ambrose and William born in 1612. The Barcroft family name is extinct in respect of the two elder sons, but the youngest son, William, went to Ireland as an officer in the army, settled there and joined the Society of Friends. The Quaker influence persisted in the Northern Ireland family down to the present century. J.B.’s parents were active members of the Society of Friends, both before and after marriage, and so also was J.B. himself for more than half his life. His father, Henry, was a man of many talents, enterprise and substantial position. He was born in 1837, became Deputy Lieutenant of Co. Down, and later, in 1890, High Sheriff of Co. Armagh. He was closely associated with the linen industry, both as secretary of the firm of Richardson and Owden, linen spinners and weavers, and as an inventor. His important invention the ‘Bossbrook Machine’ was much used in increasing the capacity of the Jacquard loom. He was also a leading promoter of the Bossbrook and Newry electric tramway in 1885, the first of all electric tramways in Ireland. In addition to charitable works he also busied himself with intellectual interests; he was the means of starting one of the first Carnegie libraries, and also a technical school in Newry. In 1867 Henry Barcroft married Anna Richardson Malcolmson, daughter of David Malcolmson of Melorew, Clonnel, Co. Tipperary.