Overheating is a problem with your hardware setup, not bitcoin. I have all too much experience with overheating while playing high resource intensive games. I've burned up 8 GB of RAM from overheating. Overheating is a much more serious danger to your equipment than just to your CPU. It can kill other components of your PC too, including your hard drives. Some people recommended some good software fixes to throttle your CPU, but you really need to invest in some cooling components to fix this problem or you could risk more than just frying your CPU. For laptops, they sell equipment like cooling pads like this one: https://www.bestbuy.com/site/enhance-laptop-cooling-stand-blue/5845304.p
Do some homework and find out which types of cooling systems would work best for your laptop. Cooling laptops is not an area I've explored. My link is just an example. You should look up your exact CPU and on the data sheet there is a range of acceptable operating temperatures (in fact you can do this with all your components and should to make sure they're operating at safe heat levels). You should always stay below the max temperatures on the data sheets. I use Open Hardware Monitor http://openhardwaremonitor.org/ to keep an eye on all my equipment. It will run in the background and tell you the max temperatures your equipment reaches, which is a very useful tool to help with tweaking how much cooling equipment you need.
Personally, I use a desktop PC with a Corsair obsidian case http://www.corsair.com/en-us/obsidian-series-450d-mid-tower-pc-case . It's easy to clean because of the magnetic pads and it has a top vent that I use a https://www.newegg.com/Product/Product.aspx?Item=N82E16835181103 Corsair Hydro H100i closed liquid cooling system to water cool my CPU. My CPU temp barley ever exceeds 55 C. It has maxed at 65-70C before in the summer when intense gaming and intense heat are in my room. This is still well below my CPU threshold of 80C. I've overclocked my graphics card (which increases heat) and I have never had any issues due to heating since while using corsair equipment. There are videos on youtube that have shown quantifiable research that certain water cooling models work best for reducing temperature over others, which is why I use the H100i.
Look at buying cooling as sort of buying a warranty for your computer. The cooler your components are running on a daily basis, the longer the lifetime of your computer since there is less chance of a hardware failure. Learn from my mistakes please. I have fried over 4 video cards, some RAM, an AMD CPU, and multiple hard drives from custom building my PCs in over a decade that I've been doing it all because I decided to skimp out on cooling. Cooling is a very important part of electronics that is often overlooked and I have had many friends whose computers have died simply because of inadequate cooling (especially in alienware type laptops for gaming). Stock cooling systems on almost any system, especially laptops, typically just suck. Good luck and godspeed.