When an Appellant argues that he proved that he sustained an aggravation of his pre-existing condition, the evidence must be supported by substantial evidence. Clark v. Peabody Testing Service, 265 Ark. 489, 579 S.W.2d 360 (1979). Substantial evidence is such relevant evidence as a reasonable mind might accept as adequate to support a conclusion. City of Fort Smith v. Brooks, 40 Ark. App. 120, 842 S.W.2d 463 (1992). The issue is not whether we might have reached a different result or whether the evidence would have supported a contrary finding; if reasonable minds could reach the Commission's conclusion, we must affirm its decision. Bearden Lumber Co. v. Bond, 7 Ark. App. 65, 644 S.W.2d 321 (1983). The test for determining whether a subsequent episode is a recurrence or an aggravation is whether the subsequent episode was a natural and probable result of the first injury or if it was precipitated by an independent intervening cause. Id. A recurrence is not a new injury but simply another period of incapacitation resulting from a previous injury. Atkins Nursing Home v. Gray, 54 Ark. App. 125, 923 S.W.2d 897 (1996). Here there was evidence that appellant has been on a pain-management program since his back surgery in 1991, that he takes pain medication three times daily, and that he has not been pain-free since surgery. There is also evidence that prior to the February 11 incident, appellant sought medical treatment for back difficulties several times. We think this constitutes substantial evidence from which the Commission could find that the February 11 incident was a recurrence of appellant's 1991 injury, rather than an aggravation. See Weldon v. Pierce Bros. Constr., 54 Ark. App. 344, 925 S.W.2d 179 (1996) (affirming Commission decision that appellant, who was pulling electrical wires through a conduit when he hurt his back, suffered a recurrence of a previous back injury where appellant had not been pain-free or without back difficulties since his initial accident). Appellant also argues that regardless of the compensability of his claim, appellees should pay for the ambulance they summoned. Appellant cites Southern Hospitalities v. Britain, 54 Ark. App. 318, 925 S.W.2d 810 (1996), in support of this argument. However, that case is distinguishable on its facts. In that case the employer initially accepted responsibility for the claim. It refused to authorize treatment by Dr. Arthur, but directed claimant to obtain treatment from Dr. Smith, which she did. The employer subsequently denied liability for any of the claimant's medical care including the cost of Dr. Smith's services and an MRI that she received while under his care. Because the employer directed the claimant to see Dr. Smith and led her to reasonably believe that the treatment would be covered by workers' compensation, the Commission held that the expenses should be borne by the employer. To the contrary, in the instant case, appellees made no such representation to appellant and summoned an ambulance only as an emergency measure when he collapsed and needed medical care.