Lack of Sweat During Jogging

Question
I 48 years old and a recreational jogger.  I have been jogging for 25 years.  I am currently jogging 5 km. 5 times per week.  The air temperature is approximately 40癈.  The problem is I do not seem to break into a sweat.  My clothes are relatively dry when I complete the jog.  Also, you would think with all this jogging I would be able to drop some weight which I put on over the past few months when I was not exercising, but this is not happening either. What could be the cause of the lack of sweat?  

Answer
Hi Pamela
You have to tell me how consistent you have been.You only say currently.Also your height weight.You could be dehydrated.How much water do you drink?Get back to me with this other info and we will pick it up from here.

The very best

John