I used to average almost one flat tire every time I went out on a Florida trail with my mountain bike.  There’s a lot of thorns, cacti, and spiky burs scattered about the off-road terrain of Florida.  You never know where your bike will travel in any adventure race.  One of the best upgrades I did to my bike was convert it to a “tubeless tire setup”.

That entails getting rid of the tube inside the tire and adding liquid sealant in there instead.  This sealant instantly reseals most punctures you may encounter in an adventure race.  Check out this video of a guy hacking holes into his bike tire.

Most wheels are able to be converted to a tubeless setup, either through using a kit or having it done by your local bike shop.  It’s quite easy for anyone with bike mechanical skills.

As an added bonus, you get a little bit of weight savings and a decent reduction in rolling mass (the liquid doesn’t roll around with the wheel).  I still recommend carrying a spare tube in case of emergencies.   This setup has reduced my flats by almost 100% (compared to once per outing, before).  Ride confidently!

Here’s a link to more resources should you be further interested.
http://www.notubes.com/help/index.aspx