All bike gloves offer this protection however a full finger glove will offer more protection than a fingerless glove.

Your comfort can be more compormised the longer you spend on the bike. The position we ride in (with our wrists extended) means that there is stretch on nerves that feed into your palm. The longer on the bike the longer these nerves are on stretch.  The combination of this stretch of nerves as well as the  compression from the pressure on the palm can cause problems such as pins and needles and numbness if you spend a lot of time on your bike. Gloves provides cushioning which relieves the pressure/compression through your palms.  This can protect some important nerves (ulnar, median) from compression type injury. Gloves also protect from the onset of any blisters or rubbing on the hands. 

Don’t rely totally on ‘protecting’ your hands with gloves.  You need to also think about your grip on the handlebar. This grip should be light and relaxed.  This can be acheived by maintaining an ‘A’ position when you ride . This position encourages  core control through a good low back and mid back position providing you with the control you need to not lean heavy on your arms and grip hard. Also when you spend a lot of time on your bike – big day rides, multi-day rides – it is important to regularly adjust your grip and be aware that as you get tired you may “lean” more heavily on your handlebars.  Be aware that downhill riding for prolonged periods of time puts more weight and therefore pressure into your hands.

Lets deal with the cold first.  Long fingered gloves insulate your hands providing warmth.  Depending on the severity of the conditions you can find varying degrees of warmth to match.  Remember you still need to maintain good control on your handlebars which means being able to grip them correctly.  This is when having the correct glove size is important and not too much bulk.If your long fingered winter gloves also need to control sweat look for mesh inserts and wicking fabrics.

In the heat, or if you tend to sweat quite a lot while riding, gloves should keep your hands dry.  Dry hands are safe hands that can maintain a good grip and control on your handlebar.  Gloves should be made from wicking fabric that absorbs and pulls mositure away from the skin.  During the warmer riding months fingerless gloves provide all the benefits of protection and comfort but allow for some airflow around the fingers.