Get some very thin silk type gloves. Silk is expensive, but there are plenty of alternative materials: nylon, etc. Amazon do a range of silk type gloves starting from around £5 a pair.
Take some normal gloves and cut off the fingers (but not the thumbs) and put them over the silk gloves. That means most of your hand will stay warm at a lower ambient temperature, plus your fingers will be free to type on a keyboard.
I found typing with silk type gloves on was awkward for the first 24 hours, but after that, I got the hang of it. But if you really can’t manage to type with gloves on, you could cut off the tips of the silk type glove finger tips, though I haven’t tried that.
As for the rest of your body, well just pile on extra layers of clothing: woolly hat and sox, extra pair of trousers etc.
And finally, note that your brain functions better when the ambient temperature is a bit below 20 deg C as compared to 25 deg C. That’s according to this Scientific American article entitled “Winter wakes up the mind…”.