How to give value of string to another string in matlab

I have a simple question. I want to calculate training heart rate.And I have some values. RHR means that resting heart rate. INTEN means fitnes level and I give values 0.55,0.65,0.8 for low, medium and high fitness level I wrote that code

 Gender=input('Please input your gender: ');
 Age=input('Please input your age: ');
 RHR=input('Please enter your resting heart rate: ');
 INTEN=input('Please enter your fitness level(low,medium or high): ');
 male=Male;
 female=Female;
 low=0.55;
 medium=0.65;
 high=0.8;
 if INTEN==0.55
 INTENT=0.55;
 elseif INTENT==medium
INTENT=0.65;
else 
INTENT=0.8;
end
 if Gender==Male
 THR=((220-Age)-RHR)*INTEN+RHR;
 elseif Gender==Female
 THR=((206-0.88*Age)-RHR)*INTEN+RHR;
 end
  disp('The recommended training heart rate is ',num2str(THR))

But it gave error why?