38 C.F.R. § 21.312 – Reduced work tolerance.

(a) General. VA will consider that a veteran with reduced work tolerance is pursuing a rehabilitation program full-time when the amount of time the veteran is devoting to his or her program is as great as the effects of his or her disability (service and nonservice-connected) will permit.
(b) Pursuit of a program. A veteran with reduced work tolerance may pursue a rehabilitation program when the following conditions are met:
1. (1) Reduced work tolerance has been determined.
2. (2) Achievement of the goals of the program are reasonably feasible;
3. (3) The IWRP (Individualized Written Rehabilitation Plan) or other plan provides for completion of the program under Chapter 31.
(c) Redetermination of work tolerance. As necessary, but not less than once yearly, the veteran's work tolerance will be reevaluated. The rate of pursuit required to meet the standard of full-time pursuit will be modified if there is either an increase or decrease in the work tolerance of the veteran.
(d) Payment of allowance. A veteran with a reduced work tolerance will be paid a subsistence allowance, at the full-time rate for the type of program being pursued, when the veteran meets the standard for full-time pursuit established for him or her in the Plan. A veteran with reduced work tolerance, who elects benefits at the Chapter 34 rate, will have to meet normal attendance requirements for that chapter, however.
(e) Determining work tolerance. A VA physician will make all determinations and redeterminations of work tolerance.
(Authority: 38 U.S.C. 3108(d))