For those wishing to add altitude training (which usually adds about 1-2% to your results but only IF you are already in excellent condition. Otherwise it is a waste of time and money) . We recommend an $80.00 mask that easily adjusts from 3,6,9,12,15,18 thousand feet. Search " training mask" on Amazon.com
ALERT. Did you know that altitude training causes tension in the rib cage and other secondary breathing muscles. That tension restricts breathing volume. FOR ANYONE. You have a bit more conditioning but your volume (or "engine" size) potential gets limited due to the tensions. What we seek is a larger engine that is also better conditioned. To offset the tensions as well as increase the volume I highly recommend our Optimal breathingkit
To Turbo Charge the entire experience of mechanics and chemistry get our O2E2
and TurboOxygen bag system.