Loses time slow

Try cleaning the battery. The battery is coated when new. I had the same problem loosing 1/2 hr some days then
Ok others

Overhaul is needed for your watch. It has mechanism, and it needs to be serviced every 4-5 years. Just imagine what would your car do without service! So, go and see the watchmaker.

The first reason can be that your battery might have died out so try and replace the battery. If it is still very slow then the hands of the watch might be lose. Or it might just have a lose spring which might need to be replaced. Its more likely to have a week battery.

I forget exactly why Paul but, I'll bet the watch is magnitized, You"ll have to see a jewler and have him/her de-magnitize the watch. Mike D

The first thing I'd recommend for a 60 year old watch is to have a watchmaker clean and oil it. Over the years the oil gets thick and gummy and slows down the watch as you're experiencing. Once it's properly cleaned and oiled the watchmaker will test and adjust it to ensure that it keeps good time. This is not a DIY job but one for a trained watchmaker with the proper tools, lubricants and experience.

Sounds like a failing battery to me. Its very common for a watch to loose time when battery needs to be changed.

I believe you are just outside your warranty. Its time to see a watch maker/technician about repairing the watch. Often times slowing is as easy to fix as lubricating the movement and forcing the gear train through the use of a cyclonic device. This fix takes minutes and is very cost effective. If the slowing is due t circuit board issues or a more sever gear train problem then the movement will need to be overhauled. I suggest comparing this cost to the cost of a replacement movement.

This could be that the battery is slow. Newer swiss watches have a indicator in the movement of the watch that makes the sweep second hand skip every few seconds to indicate that the battery is slow. On regular japan made watches the watch just simply starts slowing down. Your watch could be new but the battery in it could have a long shelf life.

There is nothing wrong with your watch. Probably it's the one measuring heart rate and pulse (heart beats per second).
Use your users manual to set the watch.
By the way: Timex is one of the worst watch producers.

Because of the way they work, it's quite hard for quartz movements to run consistently slow - so if you find one getting behind, it's usually a sign that it's stopping intermittently. It would do no harm to check that the crown is properly pushed in after you've reset it, but my guess is that the watch will benefit from a new battery. A.