SIR, I AM A 4O YEAR OLD YOUTH WITH PERFECT HEALTH. BUT , NOW A DAYS I AM FEELING THAT BOTH OF MY LEGS ARE SO TIRED THAT I CAN’T EVEN STAND PROPERLY. THIS I FEEL ONLY DURING NIGHT TIMES . AND THIS FEELING OF ENERGYLESSNESS IS ONLY ON MY LEGS. I AM A SPORTS PERSON AND I DO AVERAGE EXERCISES , SO I FEEL STRONG ON OTHER PARTS OF MY BOADY. WHY I FEEL EXHAUSTED, ONLY ON MY LEGS ? I AM AN OFFICE STAFF , SO MY WORK IS MAINLY BY SITTING THROUGHTOUT THE DAY .AND EVENING , I HAVE TO STAND IN THE TRAIN FOR HOURS. IS IT BECAUSE OF THIS ? OR, IS IT THE SYMPTOM OF ANY SERIOUS DISEASE ? PLEASE ADVICE ME SIR ?