Heat transfer through convection in human body

How does the heat transfer takes place in human body through convection in these two situations.
1) when environment temperature is less than body core temperature($37^0C)$, say it is around $25^0C$.
2) When environment temperature is higher than body core temperature($37^0C)$, say it is around $40^0C$ 3) How does the heat transfer through convection effect with varying environment temperatures say $40^0C$ and $25^0C$when we perform some physical exercise.

I have two graphs as this.
This is when environment temperature is $25^0C$ and we perform some exercises and this gives the distribution of temperature within the skin.

So at inside of skin it finally reaches the body core temperature of $37^0C$. Can you explain me why this shape of a curve is obtained when heat is transferred only through convection.

Is it because , at the outer layer of the skin it is more cool than the environment. So when air starts moving, the hot air in environment gets less densed and than the air near the skin. So the less densed air moves near to the skin and the cool air that is near the skin replaces the warm air in the temperature and thereby increases the body temperature?

This graph is when environment temperature is $40^0C$ and we perform some exercises and this gives the distribution of temperature within the skin

How can the effect of heat transfer be explained in these two graphs.

• I doubt there is significant convection in the human body. (If we define convection to be heat transport by mass transport driven by density differences caused by temperature differences). The inner of a human is not a uniform fluid. – Sebastian Riese Nov 19 '15 at 16:12
• @SebastianRiese I am workin on the bio heat equation found in academia.edu/7350650/… with the boundary condition being, $-k{dT_0(x)\over dx}=h_0[T_f-T_0(x)]$ which is convection boundary condition – clarkson Nov 19 '15 at 16:38
• Are your graphs experimental data? Heat transfer through skin is purely diffusive so I would expect linear graphs unless e.g. the thermal conductivity was variable. Does your 'model' consider formation of sweat in the second case adding additional hear transfer mechanisms? – nluigi Nov 19 '15 at 21:39