I have said in other posts, but worth repeating, that if you have an old hot water bottle, fill with cold water and add some ice. great to put your feet on, If you are working at a desk where no one can see your feet, you can put it under the desk, slip your feet out of your sandals and cool down. Or get one of those little freezer blocks that are used in lunch boxes . If you put this in a plastic bag and then put a towel round it , can be used in the same way., and can be quite a crafty thing if you put your freezer block in a plastic bag and then into an opaque bag. This can sit unobtrusively on a desk, or counter, or next to the computer. Then you can cool your hands and forearms as and when you want to.
If I need to go out shopping or walk somewhere, obviously avoid the hottest part of the day, but I notice that people here dont make the effort to walk on the shady side of a street and only cross over where necessary. I have a separate small bag into which I put a very cold bottle of water that has been in the fridge, and then also have a clean flannel which I rinse in cold water and just squeeze out , then put into a plastic bag and put next to the cold water bottle. That way the water helps to keep the flannel cool and as you go around you can drink water when you need it and your flannel will give you a chance to find a shady place and then wipe round your face, neck and hands and wrists.
Same goes for the car. I have lived abroad in places like Syria and Portugal and Britain doesnt think about having shade in car parks. So if you need to go somewhere in your car, it is worth thinking how long you are likely to be at that place, and if you have a choice of parking areas think which will be more shaded or cooler for your later time. Then again the freezer box and the cold water and cold flannel put in the side pockets, where you can use them as and when. Take a bath size towel, thickish if you have a choice. Then when you leave your car, drape the towel over the steering wheel and across to go over the seat. It can make quite a difference to getting into your car and the steering wheel is not too hot to handle.
If you have the option I prefer to go out very early in the morning and get back as soon as possible into my cool home with curtains shut etc, as by the afternoon even if it has cooled a bit , you have had the build up of heat during the day. Finally take that old wartime slogan and check "is your journey really necessary!" . If you have friends who live close by you, perhaps check and see whether you can help each other out, so if you only need a couple of things and someone is going on a main shop, ask them to get your bits and return the favour on your next big shop.
I am an eldest and am used to organising things. When my son was little, we also used to arrange to take turns looking after each others children , so that they did not have to go round the shops with parents. The shopping got done quicker and the children were much better if they only sat in the shade and coloured in pictures.
I stick to cotton, or silk and loose clothing, and at home no bra etc. Anything that is even slightly manmade fibre will not help . I dont care what looks fashionable, comfort comes first. I have a very ancient silk shirt more than 12 years old but it comes out at times like this , so long as it is clean and tidy who cares? Also in this sort of heat I go for the essentials first , rather than which shop is near another one I use. Being as comfortable as possible and being able to make that decision, that either it is worth going to one more shop to avoid coming back, or accepting you have just had enough and getting home asap.
Have always been a great believer in making two meals at once, so that you have something you can freeze or put in the fridge, so then you can make an easy meal such as having some bolognaise sauce at the ready and then just a quick sorting of pasta and you are there. Least effort and I accept that on these very hot days I am not following a balanced diet etc.but will get back to it later!
Hope that I am not teaching my grandmother to suck eggs, bit if even one idea is helpful its worth posting it. Wishing you all a cooler day and some rain!!