On the next 100 years the increase of global air temperature on 1-3°C is predicted. Such rates of air temperature growth are more rapid than previously observed. In many zones with a moderate climate the influence of warming on the human health could be considered as favourable. However in conditions of the Central Asian region, where the summer air temperature is already exceed the marginal extremes suitable for people, the thermal stress will significantly increase in the warming conditions. In this connection for planing the works and the decision of the applied problems in the field of a public health service, building, hygiene of labour and rest it is necessary to detect the present thermal stress change and to estimate it expected level under future climate scenario.

At the presented work the values of the thermal stress parameter on a territory of Uzbekistan for warm seasons are calculated with the human thermal balance method for a period since 1961 till the present time. Analysis of the series of this parameter index has shown, that some trends already exists in the level of the human thermal stress in the territory of Uzbekistan, which can be considerably increased in future with increase of temperature.

In spite of present warming up to now the values of the thermal stress parameter calculated for the day-time have not the significant trends. Analysis of the series of this parameter for night-time testifies about already usual tendency to increase the thermal stress in night period. The values of the night-time thermal stress have not reached yet the marginal extremes suitable for people night rest but under the change climate conditions this tendencies certainly will put the adverse consequences in the future.