Keeping your house too warm can make you sick and make it hard to breathe as the heat dries out the air and the warmer your house is the drier the air is.
You can wake up coughing, being dehydrated etc although if you use a humidifier you can add moisture to your home and keep your home warm at the same time.
Also sleeping in a hot room can affect the thinking ability of even healthy young adults.
It is healthier to keep your house cooler in the winter especially while you sleep.
However you don't want to keep your house too cold in the winter as too cold of a house can make you sick and affect your health.
Keeping your house at 68 F is considered healthy although anything below that temperature can become unhealthy.
Your house can feel cold at 73 F due to low humidity, poor insulation, poor heating, leaky windows, drafty windows etc.
When it's winter and your house is 73 F or above and you're still feeling cold it is likely that your house has either leaky windows, improperly sized furnace or poor insulation in your walls, attic etc.
Low humidity in the home can also lead to the house feeling colder and when it's windy out wind can also seep through the windows and cracks around your home allowing cold air into the home making it feel colder.
If your furnace is not working properly or is not properly sized the furnace won't be able to keep up and keep the house warm like it should be.
So the furnace would have to run more to keep the home warm.
Also using a humidifier in your home can increase the temperature because moist and humid air is warmer than dry air.
You can also have a whole house humidifier installed which adds humidity to the air while your furnace is running.
Also consider looking for gaps and air leaks around doors, windows, pipes etc and seal all those places up to prevent heat escaping and prevent cold air from coming into your home.
Get professional air sealing for your home and attic to seal up air leaks that are causing heat escape.
Upgrade your existing home and attic insulation to help create a solid thermal barrier to keep heat inside.
Check and repair ductwork if needed.