HIIT or Functional fitness

just wished fitness trainers put up workouts tailor made for elderly who have osteoarthritis or cartilage n tendon which are less elastic to prevent sports injuries. it takes longer for old and stiff bodies to recover from strenous workouts.my wrist recovered after i put hot compresses n deep heat rub.show us how to modify or adapt our movements.im considering which is better for aging bodies,HIIT or Tabata workouts or Functional fitness. i have to carry heavy bags of groceries,lift luggage on overhead storage space in planes,drag heavy bags of thrash,and so i need to improve functional fitness. i bought 4 dumbbells n stretchbands and now to save cost,i improvise by carrying 5 litre water bottle up 9 flights of stairs,i dont need to buy kettle dumbells as i practise filling with 2 litres of water n increasing by 0.5 litre gradually.i dont need a weighted vest for cardio conditioning when jogging as i put backback in front of chest n at the back and now im learning to walk with the bag of grocery on my head which the Indonesian cleaners do so to leave their hands free to grasp handrails n access cards. i have to reschedule hot n sweaty stuff like mopping floor n toilets to the night when temperature is cooler or i bake late at nite or cook in the wee hours of the morning as its cooler.cooking in the evening is so hot n tiring.so need to.moify my lifestyle to adjust to climate heatwave.