I wake up each day with good energy, but by mid afternoon serious fatigue starts to set in... and I don’t feel like doing anything except going to sleep...
I have recently discovered Chameleon Cold Brew coffee which has 230 mg of caffeine per 10 oz bottle... I find that it really gives me a nice pick me up... and I like the taste (Black Coffee)...
Unfortunately it wd exacerbate my tremors 
Have you tried intense exercise cycling or fast walking it defo helps
I do "high intensity" running, in the morning, when I have the energy! I tried it in the afternoon once, but my legs felt fatigued straight away. Maybe I should give it more of a try/chance. Thanks for your suggestion...
I do about 140 miles a week cycling find mornings better then I rest in the afternoons
Unfortunately this shite condition defines what we do sometimes you just have to keep fighting
I limit coffee to two cups a day. Each cup spread by over an hour. Vitamin D, coQ10, and B vitamins help energy.
Dr. Costantini has written that fatigue occurs in many pathologies and that reducing fatigue was relevant to thiamine therapy. Google: fatigue costantini
try B1, does the trick for me.
Can drinking coffee actually reduce dementia risk? – Yahoo Lifestyle
If you have PD, fatigue, low thyroid, problems with gums, and irregular heartbeat, you may want to check if you have low level mercury poisoning.
When I eat a high-carb diet, especially gluten, I have low energy to the point of really wanting a nap in the afternoon. When I cut carbs, my energy level rises. Something to maybe experiment with.
Fatigue
Addiction to coffee(?)
Coffee and Parkinson's
fatigue 
Fatigue
