Actually, everyone's body type is different and each one of us have our own limitations. Keeping this in mind I think the best person to be consulted is a doctor. To whom you can explain the basic medical problems you have and accordingly a doctor can suggest the best remedy to improve your general health. One may feel quite easy to climb stairs while another may get tired by climbing a few stairs only due to breathing problem or having some trouble in legs. Some sweat a lot while some sweat very little and naturally their tiredness differ too. So, talk to the doctor in details and ask for his guidance. I am sure it will help you a lot.

If tiredness is due to age related factors , there is not much one can do because it is natural wear and tear f the body that causes it. It is only when people relatively young and middle aged , not having any serious illness or other health complications, start feeling tired without exerting much, that one should look at the reasons. Poor dietary habits can also cause tiredness , also nagging worry ! 

It happened to me recently. Though I'm aged and never feel tired generally, owing to constant travels, exposing  myself to extreme weather conditions, I felt tired. Doctor advised me not to undertakejourneys  especially, in the present  heat conditions

Summer 2016 has absorbed everyone's energy irrespective of age and health condition. Everyone is bound to feel exhausted because of the extreme heat and scarcity of water is enhancing the health issue.  

Yes heat can really drain you of energy especially if you are out in the sun for a long period of time. I had to travel to a nearby city today to attend a function and the 90 kms combined drive in the heat and the usual traffic and noise can be exhausting ! I have taken rest from my usual  gardening and even daily walk ..

True...this year's heat has been the worst, you keep sweating profusely all day and no matter how many cooling drinks you have, you feel tired all day. Yesterday was too tiring for me, could not even rouse myself for my daily evening walk and today it still feels the same.

just think of the poor people who had to work in this hot and sweaty summer for his daily food.

There are some people like Achutanandan too who never feel tired even at 92 years if age! Truly amazing ! He shd give a tip or two to the rest of us ..

 http://m.timesofindia.com/elections-2016/kerala-elections-2016/news/kerala-assembly-polls-2016-64-rallies-13-districts-13-days-No-sweat-says-92-year-old-VS-Achuthanandan/articleshow/52264028.cms?utm_source=facebook.com&utm_medium=referral&utm_campaign=TOI

Many of you are feeling tired also due to constantly worrying about your favourite party being under constant attack by sickular and communal forces. \ and you are required to defend it with vigour in such scorching heat.

Yes. some of the members get tired in the process of defending their favorite political party in this extreme heat conditions. It's but natural.