Q10 (temperature coefficient)

The Q10 is calculated as: where; Rewriting this equation, the assumption behind Q10 is that the reaction rate R depends exponentially on temperature: Q10 is a unitless quantity, as it is the factor by which a rate changes, and is a useful way to express the temperature dependence of a process.

The Q10 coefficient represents the degree of temperature dependence a muscle exhibits as measured by contraction rates.

Values less than 1.0 indicate a negative or inverse thermal dependence, i.e., a decrease in muscle performance as temperature increases.

[4] Persons who have fallen into icy water may gradually lose the ability to swim or grasp safety lines due to this effect, although other effects such as atrial fibrillation are a more immediate cause of drowning deaths.

e.g., sharks, show less thermal dependence at lower temperatures than endothermic species [4][7]

A plot of the temperature dependence of the rates of chemical reactions and various biological processes, for several different Q10 temperature coefficients.
A plot illustrating the dependence on temperature of the rates of chemical reactions and various biological processes, for several different Q 10 temperature coefficients. The rate ratio at a temperature increase of 10 degrees (marked by points) is equal to the Q 10 coefficient.
The effects of temperature on enzyme activity. Top - increasing temperature increases the rate of reaction ( Q 10 coefficient). Middle - the fraction of folded and functional enzyme decreases above its denaturation temperature. Bottom - consequently, an enzyme's optimal rate of reaction is at an intermediate temperature.