The effectiveness of balneotherapy in relieving chronic low back pain has been scientifically proven. This project aims to study in what extent a Balneotherapy program in São Pedro do Sul Thermal Baths influences chronic low back pain of individuals aged 65 and above, and in what order of magnitude it happens, on which domains (functional, psychological, biophysical and socioeconomic) and it's repercussions. For that, the investigators intended to carry out a project subdivided into two tasks. The first, and the most complex, with a holistic approach, will be carried out by a randomized controlled study (RCT) with focus on the various biopsychosocial domains of patients with chronic lumbar pain. Concerning the second task, another RCT will be carried out aiming for statistically significant changes in the lumbar thermographic maps before and after treatment, as well as the theoretical framework of all the findings.

Inclusion Criteria:

• Patient aged 65 and over
• Low back pain with or without irradiation to the lower limbs with more than 3 months of evolution
• Imaging exam of the lumbar spine that excludes neoplastic pathology or severe structural misalignments
• Availability to carry out a 14-day treatment plan

Exclusion Criteria:

• Can't read and write
• History of fracture, surgery, infection or neoplasm in the spine
• Scoliosis with a cobb angle >20
• Lower limb muscle strength or vesico-sphincter changes
• Fever, history of recent violent trauma, unexplained weight loss, night sweats, or persistent night pain
• Others: unstable angina pectoris, poorly controlled hypertension, cardiac decompensation, respiratory failure, endocrine disorder, acute febrile condition, skin infections, fecal or urinary incontinence and psychosis or decompensated neurosis